NIST Technical Note 1797
 

Jason D. Averill
 

Lori Moore-Merrell
 

Raymond T. Ranellone Jr.
 

Craig Weinschenk
 

Nicole Taylor
 

Randy Goldstein
 

Robert Santos
 

Doug Wissoker
 

Kathy A. Notarianni
 

Edited by Kathryn M. Butler
 

U.S. Department of Commerce
 

Rebecca Blank, Deputy Secretary
 

Patrick D. Gallagher, Under Secretary of Commerce

for Standards and Technology and Director

April 2013
 

 

 

 

 

 

 

 

 

 

 

April 2013

Report on
 

High­Rise Fireground
 

Field Experiments
 

Jason D. Averill, Fire Research Division, National Institute of Standards and Technology
 

Lori Moore-Merrell, International Association of Firefighters
 

Raymond T. Ranellone Jr., Fire Research Division, National Institute of Standards and Technology
 

Craig Weinschenk, Fire Research Division, National Institute of Standards and Technology
 

Nicole Taylor, International Association of Firefighters
 

Randy Goldstein, International Association of Firefighters
 

Robert Santos, Urban Institute
 

Doug Wissoker, Urban Institute
 

Kathy A. Notarianni, Worcester Polytechnic Institute
 

Edited by
 

Kathryn M. Butler, Fire Research Division, National Institute of Standards and Technology
 

http://dx.doi.org/10.6028/NIST.TN.1797

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Certain commercial entities, equipment, or materials may

be identified in this document in order to describe an

experimental procedure or concept adequately. Such

identification is not intended to imply recommendation or

endorsement by the National Institute of Standards and

Technology, nor is it intended to imply that the entities,

materials, or equipment are necessarily the best available

for the purpose.

National Institute of Standards and Technology Technical Note1797
 

Natl. Inst. Stand. Technol. Tech. Note 1797, 152 pages (April 2013)
 

CODEN: NTNOEF
 

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Produced with the Cooperation of
 

Arlington County Fire Department
 

Alexandria Fire Department
 

Fairfax County Fire and Rescue
 

Prince William County Fire and Rescue
 

District of Columbia Fire Department
 

Montgomery County Fire and Rescue
 

Howard County Department of Fire and Rescue Services
 

Fairfax City Fire and Rescue
 

Prince George’s County Fire/EMS Department
 

Loudoun County Fire and Rescue Department
 

Metropolitan Washington Airport Authority
 

Manassas City Fire and Rescue
 

Stafford County Fire and Rescue
 

Funding provided through
 

DHS/FEMA’s Grant Program Directorate for
 

FY 2010 and FY 2011 Assistance to Firefighters Grant Program
 

Fire Prevention and Safety Grants.
 

(EMW-2010-FP-01276) and (EMW-2011-FP-00588)
 

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Abstract
 

Over the past three decades, fire department response has

expanded from fire prevention and fire suppression to

include other community services such as emergency

medical services, hazardous materials response, and special rescue.

Today, service demands and public expectations placed upon local

fire departments continue to rise as threats to communities have

increased in consequences, affected greater populations and

caused significant loss of life and property damage from both

natural and man­made disasters. However, these expectations are

currently being managed without an established technical basis

for estimating the effects of deployment decisions on fulfillment

of community expectations due to a lack of technical foundation.

Therefore, in order to balance community expectations with

limited resources, the fire service and community leaders require

scientific data that quantifies the effects of changes in fire service

deployment on the safety of the public and firefighters. This

report, along with the companion Report on Residential

Fireground Experiments (Averill et al., 2010), establish a technical

basis for deployment of resources to fireground events with

varying levels of underlying hazards.

This report presents the results of 48 field experiments and 48

complementary fire modeling simulations that collectively

quantify the impact of differing crew size deployments (3­person,

4­person, 5­person, and 6­person crews), different alarm

assignments, and different vertical response modes on occupant

survivability, firefighter safety, and property protection for four

potential high­rise fire response scenarios.

For the high­rise fireground experiments, a 13 story vacant

commercial building was used in Crystal City,Virginia. Props

were built within the structure to closely resemble an occupied

workplace including a mixture of employee cubicles and private

offices. Each floor of the structure measured approximately

30,000 sq ft (2800 m2

). This is a modest high­rise building that

represents a baseline best case scenario for high hazard1

environments.

Fire crews from 13 Metropolitan Washington D.C. area

departments were deployed in response to simulated fires within

this building. In addition to systematically controlling for the

arrival times of the fire apparatus, crew size, alarm size, and

vertical response mode were varied. Each resource deployment

performed a series of 38 tasks that were timed.

Overall, the results of this study show that the number of fire

service crew members in each company responding to a fire had a

dramatic effect on the crew’s ability to protect lives and property.

When responding to a medium growth rate fire on the 10th floor

of the high­rise structure, a 3­person crews ascending to the fire

floor confronted an environment where the fire had released 60%

more heat energy than the fire encountered by the 6­person crews.

Larger fires expose firefighters to greater risks and are more

challenging to extinguish.

In addition to the time­to­task portion of the study, fire

modeling was used to correlate time­to­task completion by crew

size, alarm size, and vertical response mode to the degree of

toxicity of the environment in the structure for a range of fire

growth rates.

Larger fires produce more risk exposure for firefighters and

building occupants. In general, occupants being rescued by

smaller crew sizes and by crews that used the stairs rather than the

elevators were exposed to significantly greater dose of toxins from

the fire. While the exact risk exposure for an occupant will depend

on the fire growth rate, their proximity to the fire, and the floor

on which the fire is located, it is clear that on­scene deployment

decisions can have a dramatic effect in determining the fate of

building occupants.

The study confirmed that a properly engineered and

operational fire sprinkler system drastically reduces the risk

exposure for both the building occupants and the firefighters.

While this has been well understood for many years and most new

high­rise buildings are constructed with fire sprinkler protection,

The National Fire Protection Association (NFPA) estimates that

41 percent of U.S. high­rise office buildings, 45 percent of

high­rise hotels, and 54 percent of high­rise apartment buildings

are not equipped with sprinklers. Moreover, sprinkler systems fail

in about one in 14 fires. Thus, fire departments should be

prepared to manage the risks associated with unsprinklered

high­rise building fires.

This study, like the Residential Fireground Experiments (Averill

et al., 2010), is a unique scientific evaluation of the relationship

between key fire service deployment variables and the resulting

service delivery outcomes. The study includes input from and was

reviewed by a comprehensive array of stakeholders, including

many of the world’s leading high­rise firefighting experts and

experienced, professional firefighters from the Washington

Metropolitan region. The results and conclusions will directly

inform local fire chiefs and elected officials charged with

matching fire risks in a community with a safe and effective fire

department deployment configuration.

These research results will inform standards development

organizations, such as the NFPA, and will allow for incorporation

into consensus industry deployment standards such as NFPA

1710, Standard for the Organizational and Deployment of Fire

Suppression Operations, Emergency Medical Operations, and Special

Operations to the Public by Career Fire Departments.

1 The NFPA Fire Protection Handbook defines hazard levels of occupancies by types. Each hazard level carries inherent risks. High­Hazard Occupancies includes —

Schools, hospitals, nursing homes, explosive plants, refineries, high­rise buildings and other high life hazard or large fire potential occupancies.

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Table of Contents
 

ABSTRACT ............................................................................................7
 

EXECUTIVE SUMMARY ......................................................................13
 

1 BACKGROUND ............................................................................19
 

2 PROBLEM ....................................................................................20
 

3 REVIEW OF LITERATURE ..........................................................21
 

3.1 Historic High-Rise Fires ..........................................................21
 

3.2 Overview of High-Rise Firefighting Tactics ............................24
 

4 PURPOSE AND SCOPE OF THE STUDY....................................25
 

5 A BRIEF OVERVIEW OF THE EXPERIMENTAL
 

FIREGROUND OPERATIONS ......................................................26
 

5.1 The Relation of Time-to-Task Completion and Risk ................27
 

5.2 Standards of Response Cover ................................................28
 

6 EXPERIMENTAL METHODS ........................................................29
 

6.1 Scenarios ................................................................................29
 

6.2 Participating Fire and Rescue Departments ............................30
 

6.3 Field Site..................................................................................30
 

6.4 Site Preparation ......................................................................31
 

6.5 Instrumentation ........................................................................33
 

6.6 Fire and Smoke Simulation......................................................33
 

6.7 Safety Protocols ......................................................................33
 

7 TIME-TO-TASK EXPERIMENTS ..................................................35
 

7.1 On-Scene Fire Department Tasks............................................35
 

7.2 Determination of Full-Alarm Assignment..................................35
 

7.3 Crew Si e ................................................................................35
 

7.4 Number of Firefighters in the Experiments ..............................35
 

7.5 Department Participation ........................................................36
 

7.6 Officer and Crew Orientation ..................................................37
 

7.7 Tasks........................................................................................40
 

7.8 Data Collection: Standardi ed Control Measures....................41
 

7.9 Task Flow Charts and Crew Cue Cards ..................................41
 

7.10 Radio Communications............................................................42
 

7.11 Task Timers ..............................................................................42
 

7.12 Search Buttons ........................................................................43
 

7.13 Video Records ........................................................................44
 

7.14 Crew Assignments ..................................................................44
 

7.15 Response Time Assumptions ..................................................44
 

8 STAGES OF HIGH-RISE FIRE OPERATIONS ............................48
 

8.1 Incident Command ..................................................................48
 

8.2 Lobby Operations ....................................................................49
 

8.3 Staging and Rehabilitation on Floor 8......................................49
 

8.4 Logistics of Material Support (Stairs/Elevators) ......................50
 

8.5 Ambulance Transport for Fire Victims ......................................51
 

8.6 Floor 9, Floor 12, and Floor 13 Search and Rescue Operations ..52
 

8.7 Floor 10 Suppression Operations ............................................52
 

8.8 Floor 10 Search and Rescue Operations ................................53
 

8.9 Floor 11 Suppression Operations ............................................59
 

8.10 Floor 11 Search and Rescue Operations ................................59
 

9 ANALYSIS OF EXPERIMENTAL RESULTS ................................64
 

9.1 Time-to-Task Analysis ..............................................................64
 

9.2 Data Queries............................................................................64
 

9.3 Statistical Methods - Time to Task ..........................................64
 

9.4 Regression Analyses ..............................................................65
 

9.5 Search Buttons ........................................................................66
 

9.6 Measurement Uncertainty........................................................68
 

10 TIME-TO-TASK RESULTS ..........................................................69
 

10.1 How to Interpret Time-to-Task Graphs ....................................69
 

10.2 Overall Scene time and Crew Si e ........................................70
 

10.3 Advance Attack Line................................................................72
 

10.4 Advance Second Line ............................................................72
 

10.5 Fire Out ..................................................................................73
 

10.6 Search and Rescue 10th Floor ..............................................73
 

10.7 Victim #1 Found ......................................................................74
 

10.8 Victim #1 Rescue ....................................................................74
 

10.9 Victim #1 Descent ..................................................................75
 

10.10 Advance Line Above the Fire (11th Floor) ..............................75
 

10.11 Search and Rescue 11th Floor................................................76
 

10.12 Victim #2 Found ......................................................................76
 

10.13 Victim #2 Rescued ..................................................................77
 

10.14 Victim #2 Descent ..................................................................77
 

10.15 Simultaneous Operations by Crew Si e ................................78
 

10.16 Summary of Regression Results ............................................80
 

11 FIRE MODELING..........................................................................84
 

11.1 Purpose of Fire Modeling ........................................................84
 

11.2 Research Question: Time to Untenable Conditions ................84
 

11.3 The NIST Fire Dynamics Simulator ........................................84
 

11.4 Development of the Design Fires for FDS Simulations ..........85
 

11.5 Ventilation................................................................................86
 

11.6 Fixed Fire Sprinkler Systems ..................................................86
 

11.7 Fire Modeling Results ............................................................87
 

11.8 Building Evacuation ................................................................95
 

12 PHYSIOLOGICAL EFFECTS ON FIREFIGHTERS ....................96
 

13 STUDY LIMITATIONS ..................................................................97
 

14 CONCLUSIONS ..........................................................................98
 

15 FUTURE RESEARCH ................................................................102
 

ACKNOWLEDGMENTS ....................................................................103
 

REFERENCES ..................................................................................104
 

APPENDICES
 

A DATA COLLECTION AND COMPANY PROTOCOLS

FOR TIME-TO-TASK TESTS ..............................................107
 

B REGRESSION COEFFICIENTS
 

C COMPARISONS USING REGRESSION RESULTS ..........124
 

D DETAILED REGRESSION RESULTS ................................132
 

E CREW SIzE PERCENT COMPARISONS ..........................138
 

F MEASUREMENT UNCERTAINTY ......................................147
 

G DEVELOPMENT OF A DESIGN FIRE ................................149
 

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Table    of Figures
 

Figure 1: High-rise building located at 223 23rd Street, Crystal City, VA............30
 

Figure 2: Office cubicle props on fire floor (10th) ................................................31
 

Figure 3: Direction signage ..................................................................................31
 

Figure 4: Fire display and smoke generator ........................................................32
 

Figure : Fire /smoke conditions on 10th floor ....................................................32
 

Figure 6: Electronic search marker ......................................................................32
 

Figure 7: Safety officer ..........................................................................................33
 

Figure 8: Crew rehab Crew hold area ............................................................34
 

Figure 9: Crew rehab Front of building ............................................................34
 

Figure : Crew rehab 8th floor ......................................................................34
 

Figure 11: Apparatus parking on site ....................................................................36
 

Figure 12: Crew resources....................................................................................36
 

Figure 13: Daily crew orientation ..........................................................................37
 

Figure 14: Officer walkthrough..............................................................................37
 

Figure : First Engine connects to hydrant ........................................................37
 

Figure 16: Driver connects to Siamese ................................................................37
 

Figure 17: Crews arrive in lobby ..........................................................................38
 

Figure 18: Crews ascend via stairs ......................................................................38
 

Figure 19: Crews ascend via elevator..................................................................38
 

Figure : Firefighters assist in moving the attack line and second line ............38
 

Figure 21: Establish line above the fire (floor 11) ................................................38
 

Figure 22: Search crew proceeds to fire floor ......................................................39
 

Figure 23: Search and rescue Fire floor..........................................................39
 

Figure 24: Search and rescue Floor above fire ..............................................39
 

Figure : Victim located on floor above fire ........................................................39
 

Figure 26: Victim descends via stairs ..................................................................39
 

Figure 27: Victim removed from building..............................................................39
 

Figure 28: Crew cue cards....................................................................................41
 

Figure 29: Task timers located throughout the high-rise structure ......................42
 

Figure : Task marker bands worn by firefighters during the experiments.......42
 

Figure 31: Search button locations on the fire floor. ............................................43
 

Figure 32: Search button locations on the floor above the fire (floor 11). ..........44
 

Figure 33: Timing for firefighter response and performance ..............................45
 

Figure 34: Route from each fire station to the fire location..................................47
 

Figure : Incident Command post ......................................................................48
 

Figure 36: Incident Command board....................................................................48
 

Figure 37: Lobby Control / Accountability ............................................................49
 

Figure 38: Lobby Control / Elevator access ........................................................49
 

Figure 39: PPV fan ventilation ..............................................................................49
 

Figure : Staging management ..........................................................................50
 

Figure 41: Elevator support ..................................................................................51
 

Figure 42: Stairwell support ..................................................................................51
 

Figure 43: Ambulance standby at high-rise structure fire ....................................51
 

Figure 44: EMS personnel exiting with victim rescued using a wheeled stretcher
 

by elevators..........................................................................................51
 

Figure : EMS personnel carry victim down stairs using a stair chair device ..51
 

Figure 46: Pathway of hose lines from core through the fire area. The double
 

dash lines represent the need for both hose lines to be present. ......................53
 

Figure 47: Schematic of the fire floor....................................................................54
 

Figure 48: Fire floor search by 3-person crew ....................................................56
 

Figure 49: Fire floor search by 4-person crew ....................................................57
 

Figure : Fire floor search by 5- or 6-person crew ............................................58
 

Figure 51: Schematic of floor 11 ..........................................................................59
 

Figure 52: Floor 11 search by 3-person crew ......................................................60
 

Figure 53: Floor 11 search by 4-person crew ......................................................61
 

Figure 54: Floor 11 search by 5-person crew ......................................................62
 

Figure : Floor 11 search by 6-person crew ......................................................62
 

Figure 56: Summary of time-to-task analysis ......................................................64
 

Figure 57: Time to complete all tasks by crew si e..............................................65
 

Figure 58: Time to complete by crew si e and ascent mode..............................65
 

Figure 59: Time to complete all tasks by crew si e and alarm si e ....................65
 

Figure : Start and end timing of critical tasks by crew si e..............................66
 

Figure 61: Button presses as a function of time on the fire floor for a 3-person
 

crew using the stairs. ..........................................................................66
 

Figure 62: Button presses as a function of time on the fire floor for a 4-person
 

crew using the stairs. ..........................................................................67
 

: Heat release rate versus time curve of a typical single cubicle fire
 

from the Cook County Administration building compared to design
 

curves of slow, medium, and fast growth (Madr ykowski et al. 2004).
 

: Heat release rate versus time of a typical single workstation fire from
 

the Cook County Administration building (Madr ykowski et al. 2004).
 

Figure 63: Button presses as a function of time on the fire floor for a 5-person
 

crew using the stairs. ..........................................................................67
 

Figure 64: Button presses as a function of time on the fire floor for a 6-person
 

crew using the stairs. ..........................................................................68
 

Figure 65: Example time-to-task graph ................................................................69
 

Figure 66: Average start and end times of critical tasks for a 3-person crew ....70
 

Figure 67: Average start and end times of critical tasks for a 4-person crew ....70
 

Figure 68: Average start and end times of critical tasks for a 5-person crew ....71
 

Figure 69: Average start and end times of critical tasks for a 6-person crew ....71
 

Figure 70: Advance Attack Line on Fire Floor......................................................72
 

Figure 71: Advance Second Line on Fire Floor....................................................72
 

Figure 72: Fire Out ................................................................................................73
 

Figure 73: Search and Rescue on Fire Floor (10th)............................................73
 

Figure 74: Victim #1 Found on Fire Floor ............................................................74
 

Figure 75: Victim #1 Rescue Removed from IDLH atmosphere....................74
 

Figure 76: Victim #1 Descent................................................................................75
 

Figure 77: Advance Line on Floor Above the Fire (11th) ....................................75
 

Figure 78: Search and Rescue on Floor Above the Fire (11th) ..........................76
 

Figure 79: Victim #2 Found on Floor Above the Fire ..........................................76
 

Figure 80: Victim #2 Rescued from Floor Above the Fire....................................77
 

Figure 81: Victim #2 Descent................................................................................77
 

Figure 82: 3-person crew task operation..............................................................78
 

Figure 83: 4-person crew task operation..............................................................78
 

Figure 84: 5-person crew task operation..............................................................79
 

Figure 85: 6-person crew task operation..............................................................79
 

Figure 86: All Tasks Complete comparing all three study variables....................80
 

Figure 87: Comparison of 3 high/4 low start, end, and duration times ..............82
 

Figure 88: Comparison of 4 high/5 low start, end, and duration times ..............82
 

Figure 89: Comparison of 5 high/6 low start, end, and duration times ..............82
 

Figure 90

..............................................................................................................85
 

Figure 91: Visuali ation of HRR for a medium growth fire for a 3-person crew
 

using the stairs (left) and a 6-person crew using the elevators (right)
 

at the time firefighters make entry to the floor.....................................87
 

Figure 92: HRR curves for the three growth fires for a 6-person crew taking the
 

stairs. The vertical line represents the Water on Fire time and the start
 

of firefighter suppression. ....................................................................88
 

Figure 93: FED contours at an elevation of 3 ft (0.9 m) on the fire floor for a
 

medium growth non-sprinklered fire at the time of firefighter entry. ..90
 

Figure 94: FED contours at an elevation of 3 ft (0.9 m) on the fire floor for a
 

medium growth non-sprinklered fire at the time the search is
 

complete...............................................................................................90
 

Figure 95: FED area percentages of the fire floor at an altitude of 3 ft (0.9 m) at
 

times of entry, victim rescue, and search complete for a
 

non-sprinklered medium growth fire. ..................................................91
 

Figure 96: Crew si e of 3 using stairs ..................................................................92
 

Figure 97: Crew si e of 3 using elevator..............................................................92
 

Figure 98: Crew si e of 4 using stairs ..................................................................92
 

Figure 99: Crew si e of 4 using elevator..............................................................92
 

Figure 100: Crew si e of 5 using stairs ................................................................92
 

Figure 101: Crew si e of 5 using elevator............................................................92
 

Figure 102: Crew si e of 6 using stairs ................................................................93
 

Figure 103: Crew si e of 6 using elevator............................................................93
 

Figure 104

..........................................................................................................149
 

Figure 105: Heat release rate versus time curve showing ignition of an adjacent
 

cubicle from the Cook County Administration building experiments
 

(Madr ykowski et al. 2004). ............................................................150
 

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List    of Tables
 

Table 1: Sixteen unique experimental variations ........................................................29
 

Table 2: Actual crew si e for each experiment ............................................................36
 

Table 3: Tasks and measurement parameters ............................................................40
 

Table 4: Go-to-work times calculated by GIS ..............................................................46
 

Table 5: Critical tasks considered in analysis ..............................................................64
 

Table 6: Average number of crews required to complete search and rescue on the fire
 

floor for each crew si e...................................................................................67
 

Table 7: Average and standard deviation of time spent actively searching the fire floor
 

as a function of crew si e. ..............................................................................68
 

Table 8: Relating FED values to percentage of population likely to be incapacitated
 

and indicating coloring scheme for visuali ation. ..........................................84
 

Table 9: Time in minutes and seconds (MM:SS) for different growth rates to reach
 

specified HRR values. ....................................................................................85
 

Table 10: Comparison of the impact of crew si e and ascent method on average
 

firefighter suppression time. ........................................................................86
 

Table 11: Sprinkler activation time and peak HRR value for slow, medium, and fast
 

growth rate fires.............................................................................................87
 

Table 12: Comparison of the impact of crew si e and ascent method on total heat
 

release prior to suppression actions. ..........................................................88
 

Table 13: FED at the time of victim rescue on the fire floor as a function of crew si e,
 

ascent method, and fire growth rate. ..........................................................89
 

Table 14: FED at 3 ft (0.9 m)elevation on the fire floor at the time of each button press,
 

as a function of crew si e and ascent method for a medium growth rate fire
 

without sprinklers. ........................................................................................93
 

Table 15: FED at 3 ft (0.9 m) elevation at the time of each fire floor button press, as a
 

function of crew si e and ascent method for a medium growth rate fire with
 

sprinklers. ......................................................................................................94
 

Table 16: Total evacuation time as a function of occupant load and evacuation
 

configuration. ................................................................................................95
 

Table 17: Effects of incrementing crew si e on begin time, controlling for ascent mode
 

and alarm si e; coefficients are in seconds...............................................132
 

Table 18: Effects of incrementing crew si e on task duration time, controlling on ascent
 

mode and alarm si e; coefficients are in seconds ....................................133
 

Table 19: Effects of incrementing crew si e on task end time, controlling for ascent
 

mode and alarm si e; coefficients are in seconds. ..................................134
 

Table 20: Contrasting high response to low response with smaller crew si es for begin
 

times; coefficients are in seconds. ............................................................135
 

Table 21: Contrasting high response to low response with smaller crew si es for
 

duration times; coefficients are in seconds. ..............................................136
 

Table 22: Contrasting high response to low response with smaller crew si es for end
 

times; coefficients are in seconds. ............................................................137
 

Table 23 Times for each crew si e to complete a task..............................................138
 

Table 24 Table 25: Array of time differences. ............................................................138
 

Table 25 Calculations of time-to-task percentages ..................................................138
 

Table 26 Sample time-to-task percentage table........................................................139
 

Table 27 Percentage Table for Overall Time-to-Task Completion by Crew Si e ....139
 

Table 28 Percentage Table for Overall Time-to-Task Completion by Crew Si e and
 

Stair/Elevator Ascent Mode ........................................................................139
 

Table 29 Table for Overall Time-to-Task Completion by Crew Si e and High/Low Alarm
 

Si e ..............................................................................................................140
 

Table 30 Percentage Table for Advance Attack Line begin time ..............................140
 

Table 31 Percentage Table for Advance Attack Line Duration..................................140
 

Table 32 Percentage Table for Advance Attack Line end time ................................140
 

Table 33 Percentage Table for Advance Second Line begin time............................141
 

Table 34 Percentage Table for Advance Second Line duration................................141
 

Table 35 Percentage Table for Advance Second Line end time ..............................141
 

Table 36 Percentage Table for Fire Out begin time ..................................................141
 

Table 37 Percentage Table for Fire Out duration) ....................................................141
 

Table 38 Percentage Table for Fire Out end time......................................................141
 

Table 39 Percentage Table for Search and Rescue 10th Floor begin time ............142
 

Table 40 Percentage Table for Search and Rescue 10th Floor duration ................142
 

Table 41 Percentage Table for Search and Rescue 10th Floor end time ................142
 

Table 42 Percentage Table for Victim #1 Found begin time ....................................142
 

Table 43 Percentage Table for Victim #1 Found duration ........................................142
 

Table 44 Percentage Table for Victim #1 Found end time ........................................142
 

Table 45 Percentage Table for Victim # 1 Rescue begin time ..................................143
 

Table 46: Percentage Table for Victim # 1 Rescue duration ....................................143
 

Table 47: Percentage Table for Victim # 1 Rescue end time....................................143
 

Table 48: Percentage Table for Victim #1 Descent begin time ................................143
 

Table 49: Percentage Table for Victim #1 Descent duration ....................................143
 

Table 50: Percentage Table for Victim #1 Descent end time....................................143
 

Table 51: Percentage Table for Advance Line Above the Fire begin time................144
 

Table 52: Percentage Table for Advance Line Above the Fire duration ..................144
 

Table 53: Percentage Table for Advance Line Above the Fire end time ..................144
 

Table 54: Percentage Table for Search and Rescue 11th Floor begin time ............144
 

Table 55: Percentage Table for Search and Rescue 11th Floor duration ................144
 

Table 56: Percentage Table for Search and Rescue 11th Floor end time................144
 

Table 57: Percentage Table for Victim #2 Found begin time ....................................145
 

Table 58: Percentage Table for Victim #2 Found duration........................................145
 

Table 59: Percentage Table for Victim #2 Found end time ......................................145
 

Table 60: Percentage Table for Victim #2 Rescue begin time ..................................145
 

Table 61: Percentage Table for Victim #2 Rescue duration......................................145
 

Table 62: Percentage Table for Victim #2 Rescue end time ....................................145
 

Table 63: Percentage Table for Victim #2 Descent begin time ................................146
 

Table 64: Percentage Table for Victim #2 Descent duration ....................................146
 

Table 65: Percentage Table for Victim #2 Descent end time....................................156
 

Table 66: Summary of Measurement Uncertainty ....................................................147
 

Table 67: Fuel properties and product yields for fuel components of design fire
 

(Tewarson 2008).........................................................................................149
 

Table 68: Peak heat release rate values from common objects ..............................149
 

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Nomenclature
 

ALS Advanced Life Support

ASME American Society of Mechanical Engineers

BC Battalion Chief

BRAC Defense Base Closure and Realignment

Commission

DAQ Data Acquisition System

ELVAC Elevator evacuation model

EMS Emergency Medical Service

FDNY Fire Department of New York

FDS Fire Dynamics Simulator

FED Fractional effective Dose

FF Firefighter

GJ Gigajoules

HAzMAT Ha ardous materials

HRR Heat release rate

IAFF International Association of Fire Fighters

IC Incident Command

ICS Incident Command System

IDLH Immediately Dangerous to Life or Health

IRIC Initial Rapid Intervention Crew

MW Megawatts

NFPA National Fire Protection Association

NFFF National Fallen Firefighters Foundation

NIST National Institute of Standards and Technology

PPV Positive Pressure Ventilation

Rehab Rehabilitation area

RIC Rapid Intervention Crew

RIT Rapid Intervention Team

SCBA Self-Contained Breathing Apparatus

SFPE Society of Fire Protection Engineers

SME Subject Matter Experts

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Executive Summary
 

Overall, the results of this study show that the number of

fire service crew members in each company responding to

a fire in a 30,000 square foot, thirteen­story structure had

a dramatic effect on the crew’s ability to protect lives and

property. This conclusion can be summarized in three principal

parts.

First, when responding to a medium growth rate fire on the

10th floor, 3­person crews ascending to the fire floor confronted

an environment where the fire had released 60% more heat

energy than the fire encountered by the 6­person crews doing the

same work. Unfortunately, larger fires expose firefighters to

greater risks and are more challenging to suppress.

Second, larger fires produce more risk exposure for building

occupants. In general, occupants being rescued by smaller crew

sizes and by crews that used the stairs rather than the elevators

were exposed to a significantly greater dose of toxins from the fire.

While the exact risk exposure for an occupant will depend on the

fire growth rate, their proximity to the fire, and the floor on which

the fire is located, it is clear that on­scene deployment decisions

can have a dramatic impact in determining the fate of building

occupants.

Third, the study confirmed that a properly engineered and

operational fire sprinkler system drastically reduces the risk

exposure for both the building occupants and the firefighters.

While this has been well understood for many years and most new

high­rise buildings are constructed with fire sprinkler protection,

NFPA estimates that 41 percent of U.S. high­rise office buildings,

45 percent of high­rise hotels, and 54 percent of high­rise

apartment buildings are not equipped with sprinklers. Moreover,

sprinkler systems fail in about one in 14 fires. Thus, fire

departments should be prepared to manage the risks associated

with unsprinklered high­rise building fires.

High­rise firefighting operations are considered high­hazard

scenarios2 because of the potential for extremely large fires and

the potentially large number of building occupants who may be

exposed to the resulting heat and smoke. Fires that are not

contained by sprinklers or other fire protection measures may

grow to consume large portions of available floor area due to the

significant time that it takes for firefighters to reach and suppress

the fire, as well as the large quantities of fuel load typical of

modern office spaces.

Additionally, high­rise buildings may have large floor areas and

many floors at or above the fire that need to be searched for possible

victims or occupants requiring assistance. Searching the fire floor is

typically conducted in high heat and low visibility conditions due to

the proximity of the fire. The remaining floors above the fire can

take substantial resources and time to fully search.

Together, the tasks and hazards typical of the high­rise

fireground combine to form a substantial operational challenge

typical of the high­hazard class of response scenarios.

Firefighting continues to be a hazardous profession; the National

Fire Protection Association (NFPA) reports over 70,000 firefighter

injuries annually (Karter, 2012), with many occurring on the

fireground. Residential fires, as examined in the NIST Report on

Residential Fireground Experiments (Averill et al., 2010), typically

dominate the fire loss statistics (property loss, civilian injuries and

deaths, and firefighter injuries and deaths) due primarily to their

frequency of occurrence. Independent of frequency, however, the

residential fireground is considered a low hazard scenario in

NFPA 1710, the national consensus standard for fire service

deployment. High­rise fires, which are the subject of this report,

pose unique operational challenges to fire service response, and

represent a high hazard life safety scenario. Key challenges include

the sheer scope and scale of conducting search and rescue

operations, difficulty moving people and equipment vertically to

the fire area, the size of the fire based on the time it takes to

initiate firefighting operations, and logistical management of the

significant number of firefighters and equipment required to

complete critical tasks.

Despite the apparent hazards however, there are no

scientifically­based tools available to community and fire service

leaders to assess the effects of fixed sprinkler systems, fire

suppression equipment or resource deployment and staffing

decisions. Though community and fire service leaders have a

qualitative understanding of the effect of certain resources

allocation decisions, there is a universal lack of a sound basis for

quantifying the total effects.

The purpose of conducting a series of high hazard, high­rise

fireground experiments is to provide quantitative data on the

effect of crew size, effective firefighting force assembly time, and

vertical­response time on the intervention capability, effectiveness

and safety of firefighters during a working high­rise, high risk

building fire on an upper floor. The results of the project will

inform the NFPA 1710 Technical Committee regarding the

optimal crew size and total effective firefighting force for a first

alarm assignment to a working high­rise or other high hazard fire.

These high hazard response scenarios will also “bracket” the

spectrum of fire response, acting as a complement to recently

published low hazard Residential Fireground Deployment Study

(Averill et al., 2010).

Satisfying several research objectives, this report focuses on the

results of the high hazard high­rise fireground experiments. For

these experiments, two stages of research were completed: (a)

fireground time­to­task experiments in a 13 story high­rise

building using simulated fire and smoke conditions, and (b)

computer fire modeling to estimate the tenability conditions in

the building as a function of the firefighter activities determined

in part (a).

2. A low hazard occupancy is defined in the NFPA Handbook as a one, two, or three family dwelling and some small businesses. Medium hazard occupancies include

apartments, offices, mercantile and industrial occupancies not normally requiring extensive rescue or firefighting forces. High hazard occupancies include schools,

hospitals, nursing homes, explosive plants, refineries, high­rise buildings, and other high life hazard or large fire potential occupancies.

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The following research question structured and guided the experimental design:

In the event of a fire on an upperfloor of a high rise building,what is the minimal fire service

deployment configuration necessary to mitigate the event effectively and safely?

More specifically, data were sought to answer the following questions about the time required to carry out tasks on the fireground

under a variety of conditions.

Time­to­Task Research Questions Fire Modeling Research Questions

1) How do crew si e, ascent mode (stairs vs. elevator) and si e 1) How do performance times resulting from different

of full alarm assignment (i.e., alarm si e low versus high) combinations of crew si e, alarm si e, vertical ascent, and

affect overall (i.e., start to completion) response timing? fixed fire sprinkler systems affect the development of

a. How do variations in crew si e affect overall response standard fire growth scenarios?

timing? 2) How do crew si e, alarm si e, vertical ascent, and fixed fire

b. How much does ascent mode affect overall timing? sprinklers affect the resulting interior tenability on the fire

c. How much does the si e of a full alarm assignment affect floor?

overall response timing?

d. How do overall response times vary by combinations of crew

si e, ascent, and alarm si e?

Based upon the research questions, 16 unique scenarios were

considered, as shown in the table below. Each of the scenarios

assumes a fire on the 10th floor of a 13 story building with an

open floor plan configuration measuring 100 ft by 300 ft (30 m by

91 m), for an area of 30,000 sq ft (2800 m2

) per floor). The fuel

load is a standard cubicle configuration, with open­wall material,

typical desk and drawer furniture, computers, printers and office

chairs. Each scenario included two victims; one located on the fire

floor and one located on the floor above the fire (Floor 11).

Scenario 1: High­alarm assignment3 with 6­person crews

dispatched to the building. Two fire service access

elevators are available for fire service use. (Best case)

Scenario 2: Low­alarm assignment3 with 6­person crews

dispatched to the building. Two fire service access

elevators are available for fire service use.

Scenario 3: High­alarm assignment with 5­person crews

dispatched to the building. Two fire service access

elevators are available for fire service use.

Scenario 4: Low­alarm assignment with 5­person crews

dispatched to the building. Two fire service access

elevators are available for fire service use.

Scenario 5: High­alarm assignment with 4­person crews

dispatched to the building. Two fire service access

elevators are available for fire service use.

Scenario 6: Low­alarm assignment with 4­person crews

dispatched to the building. Two fire service access

elevators are available for fire service use.

Scenario 7: High­alarm assignment with 3 person crews

dispatched to the building. Two fire service access

elevators are available for fire service use.

Scenario 8: Low­alarm assignment with 3­person crews

dispatched to the building. Two fire service access

elevators are available for fire service use.

Scenario 9: High­alarm assignment with 6­person crews

dispatched to the building. Stairs are available for

fire service use.

Scenario 10: Low­alarm assignment with 6­person crews

dispatched to the building. Stairs are available for

fire service use.

Scenario 11: High­alarm assignment with 5­person crews

dispatched to the building. Stairs are available for

fire service use.

Scenario 12: Low­alarm assignment with 5­person crews

dispatched to the building. Stairs are available for

fire service use.

Scenario 13: High­alarm assignment with 4­person crews

dispatched to the building. Stairs are available for

fire service use.

Scenario 14: Low­alarm assignment with 4­person crews

dispatched to the building. Stairs are available for

fire service use.

Scenario 15: High­alarm assignment with 3­person crews

dispatched to the building. Stairs are available for

fire service use.

Scenario 16: Low­alarm assignment with 3­person crews

dispatched to the building. Stairs are available for

fire service use. (Worst case)

3. Low Alarm Assignment is defined as 3 Engines, 3 Trucks, 2 Battalion Chiefs (with Aides), 2 Ambulances

High Alarm Assignment is defined as 4 Engines, 4 Trucks, 2 Battalion Chiefs (with Aides), 3 Ambulances

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Primary Findings

Of the 38 fireground tasks measured during the experiments,4

certain tasks were deemed critical, having he most significant

impact on the success of firefighting operations. All differential

outcomes described below are statistically significant at the 95 %

confidence level or better.

Overall Time To Task Completion

Overall scene time is the time that firefighters are actually

engaged in tasks on the scene of a structure fire. During the

experiments, this time included all operational tasks with the

exception of overhaul5 and salvage6. The time to completion of all

tasks decreases as crew size increases. On average, 3­person crews

took nearly an hour to complete their fire response, while crews of

6 firefighters required a mean time of just under 40 min for

completion. The performance of crews sized 4 and 5 were

in­between, with crew size 5 taking about 2 min longer than crew

size 6, and crew size 4 taking about 9 min longer than crew size 5

but 12 min less than crew size 3. Therefore, the time to complete

all task times are substantially reduced for crew size of 6

compared to 5, 5 compared to 4, and 4 compared to 3.

Advance Attack Line

As firefighters engage on a fireground, putting water on the fire

is one of the most important tasks. Extinguishing the fire is

necessary to reduce the continuously escalating risks from fire and

the toxic products of combustion. Before water can be put on a

fire, however, a hose line must be stretched from the standpipe in

the stairwell to the compartment where the fire is burning. In a

more specific analysis comparing each crew size to a 3­person

crew, the time differences increase as crew size increases. From the

initiation of on­scene firefighting activities, a 3­person crew took

1 min 43 s (8.5 %) longer than a 4­person crew to stretch the hose

line. A 3­person crew took 2 min 47 s (13.9 %) longer than a

5­person crew to complete the same task. Finally, the most

notable comparison was between a 3­person crew and a 6­person

crew, with a 4 min 28 s (22.3 %) difference in task completion

time.

Advance Second Line

The size of the fire required two 2 1⁄2 inch lines to fully suppress;

therefore a second hose line had to be advanced from the

standpipe in the stairwell to the fire. A 3­person crew took 4 min

4 s (17.4 %) longer than a 5­person crew to stretch the second

line. A 4­person crew took 2 min 43 s (12.3 %) longer than a

5­person crew to complete the same task. Finally, the most

notable comparison was between a 3­person crew and a 6­person

crew, with a 5 min 38 s (24.1 %) difference in task completion

time.

Fire Out

Extinguishing the fire out is critical to reducing risk to both

firefighters entering the structure and to trapped occupants. Fire

Out, in the study, was defined as having both the attack line and

the second hose line in place. There was a 2 min 14 s difference

(8.1 %) in the Fire Out time between the 3­ and 4­person crews.

There was an additional 1 min 15 s difference (5.0 %) in the Fire

Out time between the 4­ and 5­person crews. (i.e., 5­person crews

extinguished the fire 3 min 29 s faster than 3­person crews).

Finally, there was a 7 min 2 s difference (25.6 %) in the Fire Out

time between the 3­ and 6­person crews.

Search and Rescue 10th Floor

The fire floor was an open floor plan and contained 96 cubicles.

In the high hazard high­rise commercial building, the 4­person

crew started the search 1 min 23 s (7.8 %) faster and completed

the search and rescue 11 min 21 s (18.4 %) faster than the

3­person crews. In the same structure, the 5­person crews started

the search 1 min 4 s (6.7 %) faster than the 4­person crews and 2

min 27 s (14.1%) faster than the 3­person crew. Additionally,

5­person crews completed the search faster than the 4­ and

3­person crews by 13 min 34 s (29 %) and 24 min 55 s (42 %)

respectively. Six­person crews had the best times, starting the

search 1 min 19 s faster and completing the search 2 min 57 s

(8.0%) faster than 5­person crews. The greatest difference in

search times was between 6­ and 3­person crews. Six­person

crews started the search on the fire floor 3 min 46 s (22 %) faster

and completed the search 27 min 51 s (47 %) faster than the

3­person crews.

Victim #1 Rescued

There was a single victim located on the fire floor that was found

and rescued by all crews. A 5­person crew located the victim on

the fire floor 25 min 19 s (50.6 %) faster than a 3­person crew and

12 min 7 s (32.9 %) faster than a 4­person crew. Likewise, a

6­person crew located the victim on the fire floor 28 min 33 s

(57.1 %) faster than the 3­person crew, 15 min 21 s (41.7 %)

faster than the 4­person crew, and 3 min 14 s (13.2 %) faster than

a 5­person crew.

Four­person crews also removed the victim from the IDLH7

environment and facilitated the victim’s exit from the building 13

min 11 s (25.1 %) faster than a 3­person crew. Likewise, 5­person

crews were able to remove the victim from the fire environment

and get them out of the building 11 min 39 s (29.7 %) faster than

the 4­person crews, while 6­person crews removed the victim

from the environment and got them out of the building 14 min

58 s (38.1 %) faster than the 4­person crews and 3 min 19 s (12.0 %)

faster than the 5­person crews. Additionally, victim descent

occurred 4 min 42 s more quickly for crews using elevator rather

than stairs to get the victim out of the building.

4. In addition to the tasks denoted in this report, salvage and overhaul operations on the fireground are major tactical priorities that require significant time and

resources in order to minimize loss. These tasks however, were not included in the study scenario.

5. Overhaul is used to ensure the fire is out completely and that the environment is safe for others to enter. Firefighters may use thermal imaging cameras to look at walls

and ceilings to find hot spots, or they may tear out sections of walls and pull sections of ceilings to assure there has been no fire spread.

6. Salvage is the firefighters’ attempt to save property or reduce the damage from water and smoke. Salvage operations are typically performed immediately after a fire by

removing unharmed property from the fire area and covering it with canvas tarpaulin or other heavy protective material.

7.	 IDLH — Immediately Dangerous to Life and Health. IDLH conditions can be due to high levels of heat, smoke, or toxic gases, which rapidly threaten a person’s ability

to effect their own escape.

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Advance Line Above the Fire (11th Floor)

In a high­rise structure, it is essential to place a hose line on the

floor above the fire floor in the event of vertical fire spread. A

3­person crew took 2 min 58 s (11.5 %) longer than a 5­person

crew to complete this task while, a 4­person crew took nearly 2

min (7.8 %) longer than a 5­person crew. The most notable

comparison was between a 3­person crew and a 6­person crew,

with a 3 min 38 s (14.0 %) difference in task completion time.

Search and Rescue 11th Floor

The floor above the fire was separated into a number of

conference rooms and offices that had to be searched by each

crew. During the experiments, the 4­person crews completed the

search 9 min 31 s (18.6 %) faster than the 3­person crews.

Meanwhile, the 5­person crews started a primary search/rescue 1

min 34 s (6.8 %) faster than the 4­person crews and completed

the search 2 min 37 s (6.3 %) faster than the 4­person crews. In

the same structure, the 6­person crews also started the search 1

min 30 s (6.6 %) faster than the 4­person crews but completed the

search 5 min 8 s (12.3 %) faster than the 4­person crews.

Victim #2 Rescued

In addition to the victim on the fire floor, a second victim was

located on the floor above the fire. Each crew operating on this

floor was tasked with locating and rescuing the victim. The

5­person crews located the victim 17 min 23 s (34 %) faster than

the 3­person crews and 2 min 41 s (7.4 %) faster than the 4­person

crews. Likewise, 6­person crews located the victim on the floor

above the fire 2 min 48 s (7.7 %) faster than the 4­person crews.

Four­person crews removed the victim from the IDLH

environment and got them out of the building 14 min 33 s (27.2 %)

faster than 3­person crews. Likewise, 5­person crews were able to

remove the victim from the fire environment and get them out of

the building 17 min 9 s (32.1 %) faster than 3­person crews and 2

min 36 s (6.7 %) faster than the 4­person crews. Similarly, the

6­person crews rescued and removed the victim from the building

2 min 48 s (7.1 %) faster than 4­person crews. Additionally, victim

descent occurred nearly 6 min more quickly for crews using

elevator rather than stairs.

Summary of Regression Analysis

The effects of crew size, vertical ascent mode, and alarm size on

the timing of critical firefighter tasks were studied using standard

regression analysis. The analysis compared the times at which

each task was started, the time to complete the task, and the time

the task was completed. These timing values were given the labels

begin time, duration, and end time, respectively.

Crew Size

Going from 3­person to 4­person crews had a large impact on

advancing the attack line, advancing the second line, and begin

times for search and rescue. Reductions in times to begin these

tasks were in the range of 1 min to 2 min. Going from 4­person

to 5­person crews reduced the times to begin all critical tasks by 1

min to 2 min. Increasing crew size from 5­person to 6­person

crews showed significant reductions in begin time, just over 1

min, to advance the attack and second lines and for search and

rescue on the fire floor (10th floor).

When assessing task end times and incrementally increasing

crew size by a single firefighter (i.e., 3 to 4, 4 to 5, and 5 to 6), the

largest time improvements are seen when going from crew size 3 to

4. As firefighter crews navigate the later tasks, the improvements

cumulatively reach the 10 min to 15 min range.Very large time

improvements are seen for the 10th Floor Search and Victim #1

Rescue tasks (over 11 min) when incrementing crew size from 4 to

5. The improvements in the times to complete all tasks are

substantial (9 min to 12 min) when incrementing crew size from 3

to 4 or from 4 to 5.

Fire Service Access Elevators

All tasks were completed more than 4 min faster when the

elevators were utilized compared to stairs. Begin times for nearly

every critical task above ground level and nearly all end times

were reduced compared to stair ascent. This is because using fire

service access elevators dramatically reduced times associated

with upward and downward transport of people or equipment.

Using elevators to transport air bottles and other equipment from

the lobby to Staging allowed completion of Establishment of

Stairwell Support8 over 10 min more quickly than moving the

equipment up the stairs. Additionally, the transport of both

Victim #1 and Victim #2 from Staging to the outside of the

building was faster when using the elevators (compared to the

stairs), by 2 min 41 s and 3 min 19 s, respectively.

Alarm Size

Tasks assigned to engine 4 and truck 4, including Advancing the

Line Above the Fire, Primary Search on Floor 11 and Rescuing

Victim #2, had begin time and end time reductions since those

crews were dispatched in the first rather than the second alarm

assignment.

Combining Alarm Size and Crew Size

Given the findings from the crew size analysis that adding one or

two firefighters to a crew could generally achieve substantial task

time decreases, a logical question is whether the meaningful

benefits of a larger crew size could be realized by implementing a

higher alarm response (additional engines and trucks) at a smaller

crew size (e.g., high/4 compared to low/5).Another hypothesis is

that a high response with lower crew size might yield similar results

in task timing to that of a low response with higher crew size.

In summary,the analysis of the alarm response and crew size

combinations suggests that the benefits of higher crew size exceed

those of higher alarm assignment. Low alarm response with a higher

crew size tends to be more favorable in critical task timings than the

corresponding timings for a high alarm response with a crew size of

one less firefighter.

Combining Alarm Response and Ascent Mode

In comparing different combinations of alarm response (high,

low) and ascent mode (stairs, elevator), results contrasted several

combinations of alarm size and ascent mode.

The alarm size had virtually no effect on critical task timings,

with the exception of Primary Search of the Floor Above the Fire

(Floor 11) and Victim #2 Rescue. High alarm response realized a

mean reduction in the range of 1 min to 4 min for these tasks.

The Overall Time to Task Completion was also significantly

smaller for high alarm response by 3 min. No other task timing

comparisons were statistically different.

In the elevator scenarios, high alarm response led to eight

significantly lower timings than did a low alarm response. Results

8. Stairwell Support is also known as Ground Support, according to NFPA Standard 1561: Standard on Emergency Services Incident Management System.

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show 45 s reductions in begin time for Fire Out, Primary Search

of Fire Floor 10, and Victim #1 Found. Small reductions of just

over a minute were noted in begin times for Search of the Floor

Above the Fire (Floor 11) and Victim #2 Found. Small reductions

of 30 s to 2 min were also noted for times related to Advance the

Line Above the Fire. No other task timing comparisons were

statistically different.

Fire Modeling Results

In order to assess the hazard to occupants and firefighters as a

consequence of different deployment configurations, computer

fire modeling was performed. Three different ‘standard’ fires were

simulated using the NIST Fire Dynamics Simulator (FDS) model.

The three fires, characterized in the Handbook of the Society of

Fire Protection Engineers (SFPE) (Hadjisophocleous and

Mehaffey 2008) as slow, medium, and fast,9 grew non­linearly

with time and had burning characteristics similar to the

experimental results of typical office cubicle fires (Madrzykowski

et al. 2004).

An Fractional Effective Dose (FED)10 value of 1.0 is defined as

the toxic exposure at which 50 % of the population would be

incapacitated. The detailed probabilistic relationship between

FED and the percentage of people incapacitated is unknown.

However, an FED of 0.3 can be related qualitatively to a level that

affects vulnerable members of the population, while an FED of

3.0 will incapacitate all but the least sensitive people.

Computer fire modeling using NIST’s FDS demonstrated the

effectiveness of a working fire sprinkler system for medium

growth rate fires; the FED values remained well below a value of

0.3 for all crew sizes and ascent methods, while FED values for

non­sprinkled structures typically exceeded 1.0 at some point

during fire development. Thus, the overall hazard is greatly

improved compared to the non­sprinklered fires for both

firefighters and occupants. According to the NFPA, a working

sprinkler system is 96 % effective at controlling the growth and

spread of fires in structures (NFPA 2006). Due to a number of

high­profile fires in high­rise buildings, and considering their

demonstrated effectiveness, sprinkler systems are often required

in new high­rise buildings and many jurisdictions have required

existing high­rise buildings to be retrofitted with sprinkler

systems.

However, sprinkler systems are not installed or functional in all

high­rise buildings. According to the NFPA (NFPA 2011), 41 % of

high­rise office buildings are not protected by sprinkler systems

(compared to 25 % of high­rise “care of sick” facilities, 45 % of

high­rise hotels and 54 % of high­rise apartment buildings).

Therefore, much of this report is focused on analysis of fire

department deployment configurations responding to fires in an

unsprinklered high­rise building.

Note, further, that sprinkler systems are designed to control fires,

rather than suppress them. Fire department response is still

required even in fully­sprinklered high­rises in order to

extinguish the fire, to search for and rescue occupants requiring

assistance, and to control the sprinklers (limiting water damage).

Additionally, NFPA estimates that sprinkler systems fail to operate

in 7 % of structure fires (one of every fourteen fires) primarily

due to human error. “Two­thirds (65 %) of the sprinkler failures

to operate were because the system had been shut off before the

fire. Another one­sixth (16 %) occurred because manual

intervention defeated the system, for example, by shutting off the

sprinklers prematurely. Lack of maintenance accounted for 11 %

of the sprinkler failures and 5 % occurred because the wrong type

of system was present. Nearly all failures were therefore entirely

or primarily problems of human action. Only 3 % involved

damage to system components.” (NFPA 2006) Therefore, even

when a large proportion of high­rise buildings within a

jurisdiction are protected by sprinkler systems, the fire

department should be prepared to deploy resources to hazards

consistent with unsprinklered fires.

For unsprinklered scenarios, the time advantages gained by

larger engine crew sizes and by using elevators versus stairs.

allowing crews to complete tasks more quickly, improving the

interior conditions, including temperature, visibility, and toxicity

on the fire floor. For medium growth rate fires, firefighters

entering the environment were found to encounter fires between

5 MW to 11 MW in size, depending on crew configuration and

ascent method. This range in fire size can be visualized as the

equivalent of two cubicles on fire for a 6­person crew versus five

cubicles on fire for a 3­person crew.

Crew size and vertical ascent mode can significantly affect the

likelihood of a successful rescue of victims on the fire floor. For

victim rescue times discussed above, FED values in the cubicle

where the victim was located ranged from 0.14 (6­person crew

using the elevator) to 1.22 (3­person crew using the stairs). The

FED, based on the biological effects of toxic gases, was used to

assess the tenability of the fire environment. Consistently, smaller

crew sizes resulted in greater exposure of victims and firefighters

to combustion products compared to larger crew sizes.

Additionally, using the stairs delayed rescue and resulted in higher

toxic exposures when compared to using the elevators.

Limitations

The scope of this study is limited to understanding the relative

influence of deployment variables to the critical outcomes

associated with a working high­rise structure fire. The

applicability of the conclusions from this report to low hazard

residential fires, outside fires, terrorism/natural disaster response,

HAZMAT or other technical responses has not been assessed and

should not be extrapolated from this report. Additionally, some

important tasks, such as secondary search, property salvage, utility

control, water mitigation, building overhaul, and returning

firefighting equipment were not considered in these experiments.

These tasks delay the return of units to service and should be

considered in the design of fire department coverage. Other

limitations that affect the interpretation of the data or conclusions

are discussed in the report.

9. As defined in the SFPE Handbook, a fast fire grows to 1 MW in 2 min 30 s; a medium fire grows to 1 MW in 5 min; a slow fire grows exponentially to 1 MW in 10
 

min. A 1 MW fire can be thought of as a typical upholstered chair burning at its peak. A large sofa may produce a fire with a peak HRR value of 2 MW to 3 MW.
 

10. To characterize the accumulated hazard associated with inhalation of gases typical of combustion products, a time­integrated value known as the fractional effective

dose (FED) was used. FED is an international standard, maintained by the International Standards Organization (ISO) and documented in ISO document 13571.

FED is a probabilistic quantity used to estimate the impact of toxic gases on humans (ISO 2007). For this study, FED accounted for the effects of excess carbon

monoxide and carbon dioxide inhalation and oxygen depletion.

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Conclusions
 A total of 48 field experiments and complementary fire modeling

simulations were conducted to determine the impact of crew size,

alarm size and vertical response mode on firefighter safety and

effectiveness at a high hazard high­rise commercial structure fire.

This report quantifies the effects of changes to crew size, alarm size

and/or vertical response mode for high hazard high­rise

commercial firefighting operations in both sprinklered and

non­sprinklered buildings. While resource deployment is

addressed in the context of a high­rise structure type and high risk

level, it is recognized that public policy decisions regarding the

cost­benefit of specific deployment decisions are a function of

many factors including geography, available resources and

community expectations, as well as local hazards and risks.

Though this report contributes significant knowledge to

community and fire service leaders in regard to effective resource

deployment for fire suppression, other factors contributing to

policy decisions are not addressed.

The results provide a technical basis for the effectiveness of

company crew size, alarm size and vertical response mode to be

added to NFPA Standard 1710. The results also provide valid

measures of total effective response force assembly on scene for

high­rise fireground operations, as well as the expected

performance of time­to­critical­task measures for high hazard

high­rise commercial structure fires. Additionally, the results

provide tenability measures associated with the occupant exposure

rates to the range of fires considered by the fire model. The results

of the project will also inform code provisions in the national

model building codes which require fire service access elevators in

new construction over 120 ft (36 m).

Future research should extend the findings of this report in order

to quantify the effects of crew size and apparatus arrival times for

moderate/medium hazard or other high hazard events, such as

fires in mercantile establishments consisting of a row of stores and

restaurants, warehouse facilities, responses to large­scale non­fire

incidents, or technical rescue operations.

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1. Background
 

High­rise buildings present a unique threat to the fire

service. Multi­floor fires such as the Interstate Building

Fire, One Meridian Plaza Fire, World Trade Center

collapse, Cook County Administration Building Fire, and

Deutsche Bank Building Fire each represent serious challenges to

operational capabilities of a modern fire department.

Unfortunately, fire and city officials currently lack quantitative

data to support specific resource deployment configurations or

building code requirements germane to high­rise response

effectiveness.

The National Fire Protection Association (NFPA®) classifies

high­rise buildings as high hazard occupancies in §A.3.3.28 of

NFPA 1710®11, Standard for the Organization and Deployment of

Fire Suppression Operations, Emergency Medical Operations, and

Special Operations to the Public by Career Fire Departments. In

§5.2.3.1.2 of NFPA 1710, the standard further specifies a

minimum staffing of “five or six on­duty personnel” per

apparatus for high hazard responses. However, NFPA 1710 does

not specify a minimum deployment configuration (either

apparatus or total number of personnel) for high­rise building

fires. Rather, the standard includes a performance statement in

§5.2.4.2.3: “Fire departments that respond to fires in high­,

medium­, or low­hazard occupancies that present hazards greater

than those found in the low­hazard occupancy described [above]

shall deploy additional resources on the initial alarm.”

According to NFPA (Hall 2011), an annual average of 15,700

structure fires were reported in high­rise buildings between 2005

and 2009. The annual loss associated with these fires included 53

civilian deaths, 546 civilian injuries, and more than $235 million

in direct property damage. Office buildings, hotels, apartment

buildings, and health care facilities accounted for nearly half of

these high­rise fires. During the same span of time, most

high­rise building fires began no higher than the 6th floor, while

approximately one­third of them began on the 7th floor or higher.

11. NFPA® is a registered trademark of the National Fire Protection Association, Quincy, MA 02169. National Fire Protection Standard 1710 Standard for the

Organization and Deployment of Fire Suppression Operations, Emergency Medical Operations, and Special Operations to the Public by Career Fire Departments

contains minimum requirements relating to the organization and deployment of fire suppression operations, emergency medical operations, and special operations

to the public for career fire departments. The requirements address functions and objectives of fire department emergency service delivery, response capabilities, and

resources. The purpose of this standard is to specify the minimum criteria addressing the effectiveness and efficiency of the career public fire suppression operations,

emergency medical service, and special operations delivery in protecting the citizens of the jurisdiction and the occupational safety and health of fire department

employees. At the time of the experiments, the 2010 edition of NFPA 1710 was the current edition.

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2. Problem
 

Despite the magnitude of the fire problem in the United

States, there are no scientifically based tools available to

community and fire service leaders to assess the effects of

prevention, fixed sprinkler systems, firefighting equipment, or

resource deployment and staffing decisions. Presently, community

and fire service leaders have a qualitative understanding of the

effect of certain resource allocation decisions. For example, a

decision to double the number of firehouses, apparatus, and

firefighters would likely result in a decrease in community fire

losses, while cutting the number of firehouses, apparatus, and

firefighters would likely yield an increase in the community fire

losses, both human and property. However, decision makers lack a

sound basis for quantifying the total economic impact of

enhanced fire resources on the number of firefighter and civilian

lives saved and injuries prevented.

Studies on adequate deployment of resources are needed to

enable fire departments, cities, counties, and fire districts to

design an acceptable level of resource deployment based upon

community risks and service provision commitment. These

studies will assist with strategic planning and municipal and state

budget processes. Additionally, as resource studies refine data

collection methods and measures, both subsequent research and

improvements to resource deployment models will be afforded a

sound scientific basis.

High­rise fires represent an extraordinary challenge to fire

departments and are some of the most challenging incidents a fire

department encounters. High­rise buildings may hold thousands

of people above the reach of fire department aerial devices, and

the chance of rescuing victims from the exterior is greatly reduced

once a fire has reached flashover.

High­rise buildings were once located exclusively in larger cities,

but today they are commonly found in small and mid­sized

communities. Even if a department does not respond to a

high­rise building at present, it may in the future as urban sprawl

continues. The risk to firefighters and occupants increases in

proportion to the height of the building and the height of the fire

above grade level (Klaene, 2007). Once firefighters are operating

above the reach of aerial devices, the only viable means of egress is

the interior stairs; extra protection afforded by laddering the

building is not possible. Therefore, a sound fire department

deployment strategy, effective operational tactics, and engineered

fire protection systems cannot be separated from firefighter safety.

In attacking a fire in a high­rise building, as in any structure fire,

engine company and truck company operations must be

coordinated.

A critical variable in high­rise fire operations is the availability

of reliable elevators. If firefighters can safely use the elevators to

move people and equipment, fire­ground logistics may be

significantly improved. When the fire is located several floors

above ground level, there is a strong inclination to use the

elevators. However, fire service access elevators (engineered to

operate in a building during a fire emergency and complying with

prescriptive building code requirements and the American Society

of Mechanical Engineers (ASME) A 17.1 safety standard for

elevators) may not be available in all buildings. Therefore,

adequate stairways are necessary for firefighters to transport

equipment and reach the fire floor for suppression. Moving

supplies and staff up 10, 20, 30, or more stories is an arduous task.

If it is not properly managed, firefighters may be exhausted and

unable to fight the fire or rescue trapped occupants. Additionally,

joint use of stairways by firefighters moving upward and

occupants attempting to evacuate may increase the overall

evacuation time of the occupants, as well as delay the firefighters’

efforts to begin critical tasks such as fire suppression or search and

rescue operations.

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3. A Review of Important Literature
 

High­rise buildings were once found exclusively in urban

cities, however today they are commonly found in small

and mid­sized suburban communities as well. In many

cases high­rise buildings in suburban areas are newer, shorter, and

protected by automatic sprinkler systems. Even if some fire

departments do not respond to high­rise buildings at present,

they likely will in the future in their own communities or as part

of a mutual or automatic aid agreement.

The NFPA 101®, Life Safety Code, 2012 edition12 and the

International Code Council­published International Building

Code both define a high­rise structure as a building more than 75

ft (23 m) in height, measured from the lowest level of fire

department vehicle access to the bottom of the highest occupied

floor. For the fire service, a high­rise structure may be defined as a

building with sufficient height to exceed the fire department’s

exterior laddering capability (NFPA, 2012).

According to NFPA, there was an average of 15,700 reported

structure fires in high­rise buildings every year between 2005 and

2009. The annual loss associated with these fires included 53

civilian deaths, 546 civilian injuries, and more than $235 million

in direct property damage (Hall, 2011).

A review of historic large loss fire incidents and the fire

department response, as discussed below, revealed that the

commercial office building occupancy is commonly subject to

massive singular event losses. Consistent with the objective of the

study, this report will investigate the low­frequency,

high­consequence office fire event that poses unusual hazards for

building occupants and firefighters.

3.1 Historic High­Rise Fires

It is the intent of the study and this report to explore this

low­frequency, high­consequence­type event that poses unusual

hazards for both building occupants and firefighters. The

paragraphs that follow describe a number of these large loss

high­rise fires.

Triangle Shirtwaist

Near closing time on March 25, 1911, a fire broke out at the

Triangle Waist Factory in New York City. In less than twenty

minutes, 146 people were dead. Fire engulfed the 8th, 9th, and

10th floors of the Asch Building, occupied by the Triangle Waist

Factory. The call to fire stations went out at 4:45 pm. Firefighters

rushed to the scene but were unable to save workers trapped by

locked doors and were unable to negotiate doors opening inward.

Many occupants jumped to their deaths while others perished

inside the burning building. The firefighters’ ladders and hoses

could not reach above the 6th floor. Rescue nets were insufficient

to stop the fall of many victims jumping to flee the fire. Other

occupants trying to escape perished in the collapse of the fire

escape ladder, which did not reach the ground. The horror of the

deaths led to numerous changes in occupational safety standards

that currently ensure the safety of domestic workers today

(Cornell, 2011).

Winecoff Hotel

In 1913, the Winecoff Hotel in Atlanta, Georgia was designed

and built without sprinklers, fire escapes, or even an alarm system.

The 15­story Winecoff Hotel had one central interior stairwell

that extended from the lobby to the 15th floor, with one

additional staircase that went from the 15th floor to the roof. Each

floor had a corridor off the stairwell that led to guest rooms. On

December 7, 1946, a fire was ignited in the hotel. Shortly after the

start of the fire the only interior staircase was completely filled

with smoke and intense heat. The hotel guests were trapped in

their rooms with nowhere to go. Many guests never made it out of

their rooms; they succumbed to smoke inhalation in their sleep or

were killed by severe burns when the fire breached their doors. In

total the fire killed 119 people as they leaped from windows,

suffocated from smoke, or were burned alive. Several firefighters

were injured after being knocked off their ladders by falling

bodies.

The death toll in this fire was the impetus for national safety

codes and strict enforcement. The response to this tragedy was so

intense locally that public officials in several southern cities

ordered all existing buildings be retrofitted and brought up to

code within seven days or be shut down. Twenty­two engines and

12 ladder trucks eventually responded to the hotel fire (Winecoff

Hotel, 2013).

MGM Grand

The 1980 fire in the MGM Grand started at the rear of the casino

and eventually involved the entire casino floor measuring 150 ft x

450 ft (46 m x 140 m). The MGM Grand, now Bally’s in Clark

County, Nevada, had 3400 registered guests at the time of the fire.

Just after 7:00 on the morning of November 21, 1980, a fire broke

out in a restaurant known as The Deli. The Clark County Fire

Department was the first agency to respond. Other agencies that

responded included the North Las Vegas Fire Department, Las

Vegas Fire, and Rescue and the Henderson Fire Department.

Fire spread across the areas of the casino in which no fire

sprinklers were installed. Smoke spread into the hotel tower. A

total of 85 people were killed and 650 injured, including guests,

employees, and 14 firefighters. While the primary damage was on

the second floor casino and adjacent restaurants, most of the

deaths were on the upper floors of the hotel, caused by smoke

inhalation. Openings in vertical shafts (elevators and stairwells)

and seismic joints allowed toxic smoke to spread to the top floor

(Best, 2013).

The disaster led to the general publicizing of the fact that during

a building fire, smoke inhalation is a more serious threat than

flames. Seventy­five people died from smoke inhalation and

carbon monoxide poisoning, four from smoke inhalation alone,

three from burns and smoke inhalation; only one person died

from burns alone, and one person died from massive skull trauma

caused by jumping from a high window (Clark County FD).

The death toll, 85 people, made the MGM fire the second most

deadly hotel fire in U.S. history (Sanders, 2007) — second only to

the 119 who died in the Winecoff Hotel in Atlanta, Georgia, in 1946.

12 . The NFPA Life Safety Code is a widely used source for strategies to protect people based on building construction, protection, and occupancy features that minimize

the effects of fire and related hazards in new and existing structures.

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First Interstate

A fire in the First Interstate Bank Building in Los Angeles on May

4, 1988 destroyed four floors of the 62­story building and heavily

damaged a fifth floor. The First Interstate fire burned floors 12 to

15 and was stopped at the 16th floor. Fifty­one floors above the fire

were exposed to the fire and smoke conditions (LAFD, 1988).

The fire required a total of 64 fire companies and 383 firefighters

and took 3 1⁄2 hours to control. Despite the magnitude of this fire,

only a maintenance worker who took an elevator to the fire floor

to investigate the alarm was killed. In addition to the 383

firefighters, 17 paramedic ambulances, 17 private ambulances,

and 2 hospital disaster teams were on scene to provide emergency

medical services (EMS)(Sanders, 2007).

In 1973, the year construction was completed on the building,

sprinklers were not required for office towers. A sprinkler system

was 90 % installed at the time of the fire, but the system was

inoperative, awaiting the installation of water flow alarms. The

fire was eventually contained at 2:19 am and caused $50 million

in damages (USFA, 2010).

East 50th Street New York — Apartment Building Fire

On January 11th 1988, a fire started in an office on the first floor

of a 10­story predominantly residential high­rise. The building

was not sprinklered and had no smoke alarms, no fire alarm

system, and no emergency lighting or illuminated exit signs, but it

was still considered to be within fire code due to the age of the

building. FDNY firefighters were on scene 4 min after a call to

9­1­1. Six minutes later at 8:29 pm, a second alarm was called.

Fire spread was undeterred due to a stairwell door left open on

the fire floor. Heavy smoke quickly filled the stairwell and the

floors above the fire. Crews arriving on the second alarm were

committed to rescue operations. A third alarm was requested at

8:47 pm and a fourth at 9:15 pm. All units responding in these

assignments were committed to rescue operations on the 9 stories

above the fire. Even though interior crews had extinguished the

fire, smoke spread throughout the building, creating heavy

demand on rescue operations. At 9:42 pm a fifth alarm was

requested and brought the total firefighting force to 200 personnel

and 38 pieces of apparatus. Searches were finally complete at

10:16 pm, nearly two hours after initial crews were dispatched to

the scene. A total of 4 civilians perished and 2 civilians and 5

firefighters were injured (USFA, 1988).

Peachtree

On June 30, 1989 at 10:30 am, a small fire occurred on the 6th

floor of a 10­story office building in Atlanta, Georgia. The Atlanta

Bureau of Fire Services received a call at 10:29 am as an automatic

alarm originating at 1720 Peachtree Street, Northwest and

dispatched a normal assignment of three engines and two trucks,

an EMS unit, and a battalion chief. However, they soon received

nearly 20 phone calls in succession reporting a serious fire on the

6th floor and then dispatched an additional rescue unit and a

squad.

Extreme heat on the 6th floor required frequent rotation of

crews. The initial crew on the fire floor extinguished a large

portion of the fire but was forced to call for relief due to low air

supply.

The search for victims and survivors was complicated by the

confusing layout of the open plan offices and the fact that almost

all of the doors were locked and required extensive forcible entry.

The building was occupied, and 5 of the 40 occupants on the

sixth floor were killed, while 6 others were rescued by firefighters

using aerial ladders (Sanders, 2007). The first victim of the fire

was discovered in the hallway but was not removed immediately

due to the extent of his injuries. Of the 5 fire victims who did not

survive, 3 were removed from the building and resuscitation

efforts were attempted. A total of 23 civilians and 6 firefighters

were injured (USFA, 1989).

One Meridian Plaza

The One Meridian Plaza fire in Philadelphia, Pennsylvania,

occurred at 8:40 pm on Saturday evening, February 23, 1991. The

fire began on the 22nd floor after linseed oil­soaked rags ignited a

blaze that raged out of control for hours (NY Times, 1991).

Philadelphia firefighters fought the blaze but struggled due to a

lack of power in the skyscraper and insufficient water pressure

from the building's standpipes. More than 316 firefighters

responded in the 12­alarm fire, and 3 firefighters died after

becoming disoriented by heavy smoke (Chubb, 1991).

Firefighting efforts inside One Meridian Plaza were abandoned

due to fears the structure would collapse. The fire was brought

under control once it reached the 30th floor, which was one of the

few floors that had automatic sprinklers installed. The blaze

seriously damaged the building, destroyed eight floors, and

damaged neighboring buildings (Chubb, 1991). Because the fire

occurred outside normal working hours, the threat to occupants

was likely lessened.

1993 World Trade Center Bombing

At 12:18 pm on February 26th 1993 a vehicle bomb ripped

through the sub­grade garage levels of the World Trade Center

(WTC) in Manhattan. The blast severely damaged critical building

emergency system infrastructure, including emergency generators,

sprinkler systems, stand pipe systems, and public address systems.

Electrical power was lost in many areas of the Vista Hotel, as well

as in both Tower 1 and 2. FDNY Engine 10 and Ladder 10,

stationed near the site, felt the blast and self­dispatched, believing

it to be a transformer explosion. Upon receiving numerous 9­1­1

calls, dispatchers sent an initial deployment of 3 engines, 2 ladders,

1 Rescue Unit, and 1 Battalion Chief to the WTC complex. On

arrival, Ladder 10 noted that the garage doors at the entrance to a

garage were misshapen. Engine 10 requested a full box alarm for a

working fire, which added 3 engines, 2 ladders, 1 Battalion Chief,

and 1 Deputy Chief to the scene.

Multiple additional alarms were called to intervene in multiple

location fires including Tower 1, Tower 2, and theVista hotel located

between the towers. The magnitude of the event expanded quickly.

Due to the size of the Towers and the number of potential victims,

each building required a separate command sector. Each sector

reported directly to the incident command post.At the height of the

incident there were 156 fire companies and 31 chiefs on scene. The

event resulted in 6 civilian fatalities, 1042 injuries and a total of 16

alarm assignments dispatched to the scene (USFA, 1993).

Regis Tower

Regis Tower, at 750 Adams Avenue in Memphis, Tennessee, is an

11­story concrete­and­steel high­rise building constructed in 1964.

Its overall dimensions are 140 ft (43 m) long and 50 ft (15 m) deep.

At 02:05 am on April 11, 1994, the central station monitoring service

for the Regis Tower called the Memphis Fire Department to report

an alarm indicating a trouble alarm on the ninth floor. The normal

response to a possible high­rise fire was 3 engine companies, 2

ladder companies, and a battalion chief. The first Engine arrived

followed shortly by a truck at 02:08 am (Chubb, 1995).

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Upon arrival, firefighters encountered heavy smoke and fire on

the ninth floor. Fire companies made several attempts to rescue

occupants and extinguish the fire from the interior. The fire

self­vented, and a heavy volume of fire was visible from the

exterior. An elevated master stream was directed into the

apartment of origin to knock down any visible fire. Unfortunately,

the door between the apartment of origin and the hallway was

open, and the exterior stream pushed the fire into the 9th floor

corridor where firefighters were advancing toward the fire. As heat

and smoke conditions immediately became worse on the 9th

floor, firefighters were forced to retreat. Two firefighters became

disoriented and had to be rescued. Two firefighters and two

civilian occupants were killed (Sanders, 2007).

Cook County Administration Building

On October 17, 2003, a fire on the 12th floor of the 37­story

Cook County Administration Building in Chicago, Illinois

resulted in 6 civilian fatalities. The fire was believed to have

originated in a closet within a 2629 sq ft (244 m2

) suite of offices

on the east side of the 12th floor. Due to fire­resistive building

features, fire damage was contained to the office suite, but smoke

and fire traveled to the entire 12th floor. The fire self­vented

through eight exterior windows on the east side of the suite,

creating the potential for floor­to­floor fire extension on the

exterior.

Upon arrival, firefighters were faced with an intense fire that

they were unable to extinguish from an interior hallway position.

Elevated master streams were used to knock down the fire from

the exterior. Interior hose streams were then redeployed to achieve

final extinguishment. Tight compartmentalization and closed

office doors contained the fire to the suite where it originated

(Sanders, 2007).

Deutsche Bank

On August 18, 2007 two fire fighters lost their lives while

operating at a 7 alarm fire at a high rise in Manhattan, New York

City. The 41­story Deutsche Bank was undergoing deconstruction

and asbestos abatement due to the damage sustained after the

collapse of the World Trade Center Buildings on September 11th,

2001. In the process of deconstruction, the building layout

included maze­like partitions installed to prevent the spread of

asbestos during abatement. The standpipe system was also being

disassembled.

A fire broke out at 3:30 pm on the 17th floor, with an initial first

alarm being sent at 3:37 pm. After confirmation of the fire, a full

alarm response was sent along with additional units. This

response included 4 engines, 3 ladders, 2 Battalion Chiefs, 1

Division Chief, 1 Squad, 1 Rescue, 1 HazMat, 1 HazMat Battalion

Chief, and Chief aides, for a total of 65 firefighters. A second

alarm was requested 5 min later, to which an additional 12

Engines, 7 Trucks, 10 Battalion Chiefs, 1 Division Chief, 3 Deputy

Chiefs, 1 High Rise Engine, 1 Field Communication Unit, 1

Squad, 1 Rescue with Battalion Chief, and various other support

apparatus responded. The second alarm brought an additional

160 personnel for a total of 225 firefighters on scene.

A construction worker reported that the fire was on the 17th

floor, so initial crews took a construction elevator to the 15th

floor. An engine crew attempted to connect 2 1⁄2 inch lines to the

standpipe in the stairwell and found no connections on the 14th

or 15th floors. The crew then checked the 16th floor to learn that

it was blocked by a wooden hatch. The interior stairwells had

hatches installed every two stories, which limited the movement

of the firefighters between floors. Some hatches were opened by

fire crews using saws, but even with open hatches only one

firefighter could pass though at a time.

Engine 10 crew eventually located a connection to a standpipe in

a second stairwell and flaked out several lengths of hose then

waited for water. Ultimately, it was discovered that the standpipe

system was completely out of operation and was disconnected in

the subterranean levels.

As the fire continued to spread uninhibited, Command ordered

the crews back down to the 14th floor, as the fire was now burning

on the 15th floor with heavy smoke and still no water in the

standpipes.

At 4:14 pm a firefighter on the Engine 10 crew transmitted a

Mayday after becoming disoriented. Firefighters responding to the

Mayday found their way off the 15th floor though a breach in a

plywood wall. Several crews were on the 15th floor either trying to

find their way out, or searching for the lost firefighter. Eventually,

all firefighters were ordered to exit the 15th floor as heat

conditions were becoming more severe.

As conditions continued to worsen on the 14th through 17th

floor, engine crews began to drop hose lines on the exterior of the

building. Once the exterior hose stretch was complete, additional

lengths were attached to reach the seat of the fire. The hose line

was charged with water at 4:44 pm, over an hour after the initial

crews were dispatched.

Following a tenuous fire fight by firefighters from 45 Engine

Companies, 30 Ladder Companies, 3 Rescue Companies, 19

Battalion Chief Units, 4 Division Chief's Units, and numerous

other special and support units operating with little to no

visibility, the fire was suppressed. As a result of the high risk

environment, 115 firefighters were injured and two firefighters

were killed (IFSTA, 2011).

Wellesley Street, E., Toronto, Ontario, Canada

On September 24, 2010, a six­alarm fire at a downtown Toronto

high­rise building resulted in 14 people being sent to hospital and

left an estimated 1,200 people temporarily homeless. Eight adult

civilians, three firefighters and three children required medical

care, while an additional 10 firefighters were treated for heat

exhaustion (Allen, 2010).

The fire at 200 Wellesley Street, East started at 5:00pm on the

24th floor and spread to two adjacent units. It grew into a

six­alarm fire, with more than 120 firefighters and 27 pieces of fire

apparatus at the scene. At 8:30 p.m., when it seemed progress has

been made, bright orange flames could still be seen in the

bedroom of one unit on the 23rd floor (Allen, 2010).

The growth of the fire was attributed to extreme fuel loading in

one apartment. Ontario Fire Marshal described the fire fuel load

as one of the worst hoarding fires in Canada. The tremendous

growth and spread of the fire was a result of the excessive amount

of combustible materials stored on the balcony and in the suite of

origin. The extreme fuel load made the fire very difficult to fight,

control and extinguish. Firefighters deemed the fire one of the

hottest and most deep­seated fires they had ever fought and high

winds made matters worse. Four hours after the blaze began,

firefighters were still battling spot fires, created from falling

debris. By 10 p.m., firefighters appeared to have knocked the

flames down (CTV, 2010).

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Shanghai, China

On November 15, 2010, a fire destroyed a high­rise building in

Shanghai, killing 58 people and injuring at least 90 others as the

blaze tore through a 28­story block of flats in Shanghai. The

building was being renovated when the fire started. The

investigation of the fire made a preliminary conclusion that

negligence by unlicensed welders on the tenth floor caused the

bamboo scaffolding and attached nylon netting to ignite. Fire

subsequently spread to the entire structure through ignition of the

polyurethane foam insulation used on the building's outer walls.

Many people were trapped as fire engulfed the upper part of the

building, beyond the reach of the fire hoses, while others were

clinging to scaffolding surrounding the building as they waited to

be rescued from the flames. Helicopters attempted to rescue some

from the roof.

Firefighters battled for several hours to bring the blaze under

control. More than 80 fire engines were called to battle the fire. By

the time the fire was brought under control, more than 100

people had been rescued (BBC, 2010).

Lakeview High Rise/Chicago

NBC Chicago reported that a fire broke out on the 12th floor of

the building around 2 am on October 25, 2012. When a man and

a woman living on the floor escaped with their dog they left their

front door open, and the super­heated toxic gases from the fire

spread into the hallway. The heat was near 1,500 degrees

Fahrenheit at the ceiling, and a woman returning to her North

Side apartment was killed when she took the elevator to her floor

­­ not knowing that a fire was raging in the hallway outside her

apartment. When elevator doors opened on the 12th floor, the

woman was standing in the elevator and likely exposed to direct

fire spread. Nine other people, including two firefighters, were

injured in the blaze (Chicago Tribune, 2012).

3.2 Overview of High­Rise

Firefighting Tactics

In a high­rise fire, the risk to firefighters and occupants increases

in proportion to the height of the building and the height of the

fire above ground level. When firefighters are operating above the

reach of aerial devices, the only viable means of egress is the

interior stairs; extra protection afforded by laddering the building

is not possible (Klaene, 2007). As the level of the fire floor gets

higher, reliance on the standpipe also increases. Open­layout floor

plans such as office buildings with cubicle farms can challenge

both the standpipe’s flow capacity and fire department resources.

A working fire in a high­rise building can threaten thousands of

occupants and hundreds of responding firefighters. The most

effective way to extinguish a high­rise fire is by mounting an

offensive attack as early as possible, because in the vast majority of

historic high­rise fires the best life safety tactic is extinguishing the

fire. Good high­rise firefighting tactics and firefighter/occupant

safety cannot be separated.

Tactics are a series of operational tasks that in combination

accomplish an overall fireground strategy. Individual tactics are

measurable and attainable intermediate outcomes that lead to the

completion of incident objectives like extinguishing the fire.

There are three tactical priorities in a high­rise fire; life safety, fire

extinguishment, and property conservation (Klaene, 2007). After

the fire is out, salvage and overhaul tactics are employed.

During firefighting, life safety tactics fall under the label of

Search and Rescue. Search is a fireground tactic that is a

systematic approach to locating possible victims, and Rescue is

the act of removing victims from known danger. Searches are

normally conducted by an entire crew, supplemented by an attack

or ventilation crew. The minimum number of firefighters for a

search is two (IFSTA, 2010).

Fire extinguishment is a critical factor, since the intensity and

size of the fire will determine the extent to which combustion

gases are heated and how high they will rise inside the building.

Building suppression systems, both active and passive, can impact

fire growth, occupant safety, and firefighter safety and

effectiveness. Such features include active fire detection and

automatic sprinkler systems. Once firefighters are on scene, they

will complete a series of fire confinement and extinguishment

tasks. Firefighters access the structure, locate the fire, locate any

avenues of spread, place hose lines, and establish a water supply.

Once a water supply is established, water should be placed at the

seat of the fire or in the compartment containing the fire to

extinguish it.

Ventilation is a tactic that affects both life safety and fire

extinguishment. Coordinated ventilation may be implemented at

any time during the operation, but it should be coordinated with

suppression and interior rescue activities.Ventilation is used to

channel and remove heated air, smoke, fire gases, and other

airborne contaminants. Applying proper ventilation at the right

time and place is key to firefighter and occupant safety.Venting at

the wrong time or place can draw active fire toward fresh air,

which will injure or kill anyone in its path.

After the fire is extinguished and victims rescued, firefighters

should move on to the task of salvage. Salvage is the firefighters’

attempt to save property or reduce the damage from water and

smoke. Salvage operations are typically performed immediately

after a fire by removing unharmed property from the fire area and

covering it with canvas tarpaulin or other heavy protective

material. Salvage is a major tactical priority that requires

significant time and resources in order to minimize loss. Salvage

and overhaul operations (described below) were not included in

the study scenario.

Overhaul is the completion of the extinguishment, which can

result in what may appear to be additional damage to any

property. The additional damage, however, is warranted to

prevent more unexpected fire damage. Overhaul is used to ensure

the fire is out completely and that the environment is safe for

others, such as investigators or the property owner, to enter.

Firefighters may use thermal imaging cameras to look at walls and

ceilings to find hot spots, or they may tear out sections of walls

and pull sections of ceilings to assure there has been no fire

spread.

As indicated by the tasks that must be accomplished on a

high­rise fireground, understanding the required resources is

critical. The number of firefighters needed to safely and effectively

combat a high­rise fire may be large. Although an offensive fire

attack is the preferred strategy whenever conditions and resources

permit, a defensive attack that limits operations to the outside of a

building and generally results in more property damage must be

considered when risks to firefighter safety are too great and

benefits to building occupants are negligible. The offensive vs.

defensive decision is based on a number of factors: fireground

staffing available to conduct an interior attack, a sustained water

supply, the ability to conduct ventilation, and risk vs. benefit

analysis regarding firefighter and occupant safety.

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4. Purpose and Scope of the Study
 

This project systematically studies the deployment of mobile

and personnel resources and their affects on firefighter

safety, civilian safety, and the protection of high­rise

property. The purpose of the study is to enable fire departments

and city/county managers to make sound decisions regarding

optimal resource allocation using the results of scientifically based

research.

Many variables may have an effect on the outcome of a high­rise

fire. Due to limited resources, only variables considered likely to

have the most significant effect on the outcome of the fire

incident were included in the scope of the study. These variables

included crew size, alarm size, and vertical response mode (stairs

or elevators).

The results of the project will inform the NFPA 1710 Technical

Committee regarding the optimal crew size and total effective

firefighting force for a first alarm assignment to a working

high­rise or other high hazard fire. The results of the project will

provide valuable information for those developing national model

building, fire, and life safety codes. Finally, these high hazard

response scenarios will “bracket” the spectrum of fire response,

acting as a complement to the recently published low hazard

Residential Fireground Deployment Study (Averill et al., 2010).

This report describes the experiments that were conducted using

on­duty fire service personnel and computational tools to

simulate a response to a high­rise fire incident on an upper floor

of a building. The experimental design and fire modeling

methods are similar to those conducted in the Residential

Fireground Deployment Study.

There were two parts of the experiments.

n Field tests for critical time­to­task completion of key tasks in

fire suppression and in occupant search­and­rescue

n Fire modeling to determine the effects of firefighter operations

on fire growth and spread and on occupant survivability

The scope of this study is limited to understanding the relative

influence of deployment variables on high hazard high­rise

structure fires, similar in magnitude to the hazards described in

NFPA 1710. This standard is limited in that it does not specify the

precise nature of a high hazard high­rise structure fire. Therefore,

a secondary objective of this study is to establish a technical basis

for deployment of firefighters and equipment to a “typical”

high­rise fire. While all fires and buildings have unique features

and characteristics, it is believed that the building and operations

used in these experiments are broadly representative of a high

hazard fireground and will be useful in establishing the technical

basis underlying the national standard for minimally safe and

effective deployment.

When paired with the Residential Fireground Report (Averill et

al., 2010), a significant benefit of this report is the ability to

compare and contrast deployment outcomes for a range of hazard

scenarios. A residential fire represents a low hazard, relatively high

frequency scenario and a high­rise fire is a high hazard, relatively

low frequency scenario. Note that the applicability of the

conclusions from this report to outside fires, and response to

hazardous material incidents, acts of terrorism, and natural

disasters or other technical responses has not been assessed and

should not be extrapolated from this report.

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5. A Brief Overview of High­Rise Fireground Operations
 

Regardless of the size of the burning structure, firefighting

crews identify four priorities: life safety of occupants and

firefighters, confinement of the fire, property conservation,

and reduction of adverse environmental impact. Interdependent

and coordinated activities of all firefighting personnel are

required to meet the priority objectives.

High­rise fire response is a complex orchestration, often involving

over 100 personnel operating over many floors in a building. While

the exact sequence of operations may vary from one fire department

to another and even from one fire to another depending upon the

exact nature of the event, the following narrative describes the

general sequence of activities during a high­rise fireground

operation. Note that some activities,such as fire suppression or

victim rescue, are considered milestone events because they are

critical to the priority objectives noted above. The following

overview is derrived largely from Klaene and Sanders (2007).

The First Arriving Fire Crews:

n The first engine positions the apparatus such that it can

establish an uninterrupted water supply to critical building

systems, including the standpipe and sprinkler system (if

present) and operates the pump hydraulics at the apparatus as

the remaining crew members enter the building.

n The first arriving officer establishes command (Incident

Command) and conducts initial size­up by checking the alarm

panel and consulting with building management. One firefighter

or officer is assigned to the lobby to establish Lobby Control.

n Remaining firefighters and officers ascend the stairway to an

area two floors below the fire via stairs when the elevator is

unsafe for use or by elevator when the elevator is determined

to be safe for use by firefighters. This crew sets up a staging

area to hold firefighters preparing to fight the fire or to

conduct search and rescue.

n Some crew members proceed to the next floor up (one floor below

the fire). Upon arrival at the floor below the fire, one crew enters

forthe purpose of viewing the general floorlayout in preporation

for entering the fire floor.This crew also does a quick check forfire

extension and connects a hose to the standpipe on that floor.

n Prior to being charged with water, a hose line (200 ft (61 m) of 2

1⁄2 inch hose) is stretched from the standpipe on the floor below

the fire to the stairwell on the floor above the fire.It is then looped

back in the stairwell in preparation for entry to the fire floor.

n An Initial Rapid Intervention Crew (IRIC) is assembled on the

staging floor prior to crews entering the fire floor. The NFPA

and OSHA “2 In/2 Out”13 crew is designated prior to anyone

entering an atmosphere that is immediately dangerous to life

or health (IDLH)14. A full and sustained Rapid Intervention

Crew (RIC) is assembled as soon as sufficient personnel arrive

on scene to do so.

n Once fully charged with water, the hose line is advanced

through the doorway into the fire floor hallway. Ceiling tiles

(or ceiling if no tiles present) are pulled open to check for fire

extension as the crew advances down the hallway toward the

initial fire area. Checking the ceiling ensures that the crew will

not become trapped due to a hidden fire in the overhead

space.

n If fire extension has not progressed beyond the initial fire

compartment, entry is forced into the fire compartment area.

n The hose line is extended into the fire compartment area and

operated to extinguish the fire.

As Other Fire Crews Arrive:

n Upon arrival, a command officer (Battalion Chief 1) receives

command transferred from the initial Incident Commander (IC).

n Upon arrival, Battalion Chief 2 is assigned as a Division

supervisor on the fire floor and supervises all operations on

that floor.

n After leaving a crew member in the lobby to place a high

pressure mechanical fan in the stairwell in order to keep the

stairwell free of smoke, a crew ascends to the fire floor to begin

a search for any victims.

n All arriving crews are directed to the staging area two floors

below the fire floor, with the exception of later arriving larger

crews that may first report to Base (staging outside the

building) pending assignment.

n A second hose line, also 200 ft (61 m) of 2 1⁄2 inch hose, is

advanced from the standpipe on the fire floor to the fire area

and is operated to extinguish the fire.

n One company of firefighters is assigned to Stairwell (or

Elevator) Support to transport necessary supplies (Self

Contained Breathing Apparatus (SCBA) air cylinders, water

for hydrating firefighters, search ropes, etc.) to the staging

floor for crews working in the building.

n A rehabilitation area is established two floors below the fire

adjacent to the staging area in order to conduct a physical

assessment of firefighters who have completed a unit of work

(commonly the consumption of one air bottle by a firefighter

or a predetermined time period).

n A crew is assigned to check for fire extension on the floor above

the fire with a 2 1⁄2 inch hose line.A second hose line supplied by

the floor above the fire standpipe is also deployed to that area.

n A crew is also assigned to conduct search and rescue

operations on the floor above the fire.

n Crews are also assigned to upper floors (above the floor above

the fire) to search the floors and both stairwells.

n Stairwells are ventilated using positive pressure ventilation

(PPV), which includes opening a hatch at the top of the

stairwell after the fire is reported to be out.

13. The "2 In/2 Out" policy is part of paragraph (g)(4) of OSHA's revised respiratory protection standard, 29 CFR 1910.134. This paragraph applies to private sector

workers engaged in interior structural firefighting and to Federal employees covered under Section 19 of the Occupational Safety and Health Act. States that have

chosen to operate OSHA­approved occupational safety and health state plans are required to extend their jurisdiction to include employees of their state and local

governments. OSHA’s interpretation on requirements for the number of workers required being present when conducting operations in atmospheres that are

immediately dangerous to life and health (IDLH) (OSHA 1995) covers the number of persons who must be on the scene before firefighting personnel may initiate an

attack on a structural fire. An interior structural fire (an advanced fire that has spread inside of the building where high temperatures, heat, and dense smoke are

normally occurring) would present an IDLH atmosphere and therefore require the use of respirators. In those cases, at least two standby persons, in addition to the

minimum of two persons inside needed to fight the fire, must be present.

14. IDLH — Immediately Dangerous to Life and Health. IDLH conditions can be due to high levels of heat, smoke, or toxic gases which rapidly threaten a human’s

ability to affect their own escape.

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n Later arriving Chief Officers are assigned to:

• Division Supervisor on floor above the fire.

• Staging

• Upper Division (upper floors)

• Safety

• Planning (formerly the IC as higher ranking chief officer

assumes command)

• Operations

• Public Information

• Logistics

• Lobby Control (If the initial lobby control assignment was

not an officer)

As shown by the assignments, the first tactical priorities are

extinguishing, or at least controlling the fire and conducting a

primary search and rescue in the immediate fire area; these task

must include an IRIC team before suppression or search tasks can

proceed. Successful fire control stops forward progress of the fire

and protects crews conducting search and rescue activities,

whereas extinguishment dramatically reduces the magnitude of

the hazard.

The role of the Incident Commander is to develop an incident

action plan to mitigate the incident and see that those actions are

carried out in a safe, efficient, and effective manner. Command

aides are responsible for assisting with situational assessment and

communications with division, group, and crew officers to ensure

personnel accountability.

The response time and interval between units arriving at the

scene varies based on geographic distance from the station

location of each company to the fire address (as well as any traffic

or weather conditions). Companies dispatched from locations

further from the incident address will generally take longer to

arrive.

Throughout the entire incident, each crew officer is responsible

for the safety and accountability of his or her personnel, including

air management. The location and wellness of crews is tracked by

the division supervisor’s command aide through a system of

personal accountability checks conducted at 20 min intervals.

Overall incident accountability (resource status/situation status)

is monitored by the Planning Chief and his or her resource status

staff.

Air consumption and fatigue are major factors when a

continuous attack or prolonged search and rescue are required.

This is particularly true in buildings where firefighters must

ascend to an upper floor via the stairway when the elevators are

unsafe to use. When an extended operation is anticipated, a plan

is required to relieve firefighters performing essential tasks in

areas immediately dangerous to life and health before they deplete

their air supply or become incapacitated due to exhaustion. All

firefighters who complete a work assignment, who are exhausted,

or are relieved due to low air supply are sent to a rehabilitation

area, where they are medically evaluated, provided liquids, and

taken out of service to rest. After a rest period of at least 15 min,

firefighters are moved forward to the staging area where they

replace their air cylinder and continue to rehabilitate while

awaiting reassignment. The rehab area and staging area are

usually on the same floor (at least two floors below the fire floor),

but separated from one another to avoid confusion and

premature reassignment of fatigued firefighters.

SCBA air cylinders, medical supplies, water and other needed

firefighting supplies are moved from the outside at ground level to

the staging and rehab areas by stairwell support personnel.

Stairwell support provides a means of moving supplies from the

first floor to the rehab/staging area by placing a firefighter on

every other floor or so. Typically, firefighters are assigned to bring

air cylinders and other equipment into the building using an

elevator to transport equipment to the staging and rehab areas.

Once the fire is located and extinguished and occupants are

rescued or evacuated, the IC reassesses the situation and develops

a revised incident action plan. At this point, the Incident

Commander either reassigns crews or calls additional companies

to the scene to conduct a very thorough secondary search of the

building, verify that the fire has not extended into void spaces,

determine that the fire is fully extinguished, and conduct salvage

and overhaul operations. These activities are important and

should be completed as soon as possible since they can reduce the

chance that the fire re­ignites and can significantly limit the extent

of property damage. Personnel assigned to the secondary search

should not be the same personnel who conducted the primary

search. Due to limited resources, salvage, overhaul, and secondary

search activities were not part of this high­rise experiment.

5.1 The Relation of Time­to­Task Completion and Risk

The goal of a properly designed fire department deployment

strategy is to match the deployment of resources to the risks

associated with different events. The community risk level is

typically established through an overall profile of the community

based on its unique mixture of demographics, socioeconomic

factors, occupancy risk, fire management zones, and the level of

services currently provided. Given that a particular hazard exists

in a community, the consequences of an emergency event (e.g.

fire) in such a hazard are ultimately determined by the mitigation

efforts.

During any fire incident, the risks to firefighters and occupants

are strongly correlated with how long it takes to implement

mitigation strategies. This is particularly true in the high­rise

scenario due to the scale of the response requirements and the

potential number of building occupants who may be exposed to

the risk. Critical Tasks for high­rise firefighting operations include

fire suppression and completion of search and rescue operations,

among others. Anything that delays the accomplishment of these

critical tasks, whether it is due to the deployment of inadequate

resources or to other factors such as delays in detecting the fire,

delays in reporting the fire, or difficulty in accessing the building,

reduces the likelihood of controlling the fire in time to prevent

major damage, injuries, or possible loss of life, and increases the

level of effort and danger to firefighters.

On any fireground, fighting larger fires means additional risks to

both firefighters and occupants. During a significant building fire,

smoke, heat, and fire are transported throughout the building.

The rate and extent of travel depend on the nature and quantity

of the fuel available to burn, the size of the fire compartment,

available ventilation and other factors. The temperature of a

compartment fire may rise to over 1,000 °F (540 °C), and toxic

gases can accumulate to lethal levels rapidly. Therefore, the IC

must prioritize the deployment of firefighting resources in order

to accomplish priority tasks as quickly as possible, without

compromising the safety of the firefighters or occupants in the

process. Accomplishing these objectives requires strong

situational awareness, communication with division, group, and

company officers, and a shared understanding of the tactical

priorities across the fireground.

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5.2 Standards of Response Cover

Developing a standard of response cover—the policies and

procedures that determine the distribution, concentration, and

reliability of fixed and mobile resources for response to fires (as

well as other kinds of technical response)—related to service

commitments to the community is a complex task. Fire and

rescue departments must evaluate existing (or proposed)

resources against identified risk levels in the community and

against the tasks necessary to conduct safe, efficient and effective

fire suppression at structures identified in these risk levels. Fires in

high hazard/high­risk buildings, such as the high­rise building

used for this experiment, require more fire department resources

in a shorter period of time than do fires in a typical lower­risk

residential building such as a single family dwelling. It is essential

that the risks be evaluated based on the potential life safety, fuel

load to be extinguished, and property conservation challenges.

Leaders must also evaluate geographic distribution and depth or

concentration of resources deployed, based on time parameters.

Recognition and reporting of a fire sets off a chain of events

before firefighters arrive at the scene, such as call receipt and

processing, dispatch of resources, donning of protective gear, and

travel time. NFPA 1710 defines the overall time from dispatch to

scene arrival as the total response time. This standard divides total

response time into a number of discrete segments, of which travel

time is defined as the time interval from the beginning of travel to

the scene to the arrival at the scene.

Arrival of an effective firefighting response force must be

immediately followed by organization of the resources into a logical,

properly phased sequence of tasks,some of which need to be

performed simultaneously. Knowing the approximate time it takes

to accomplish each task with the allotted number of personnel and

equipment is critical. Ideally, crews should arrive and intervene in

sufficient time to prevent flashover or fire spread beyond the room

of origin. Failure to prevent flashover affects the ability to safely

remove occupants and to rescue persons who cannot self­evacuate.

Decision­making regarding crew size,staffing levels and geographic

distribution of resources must consider the times when

simultaneous completion of tasks is required. There should be

sufficient redundancy or overlap in the system to allow for

simultaneous calls and high volume of near simultaneous responses

without compromising the safety of the public or firefighters.

Policy makers have long lacked studies that quantify changes in

fireground performance based on apparatus crew size and

on­scene arrival time intervals. The experiments in this study

were designed to observe the effect of these variables including

company crew size, apparatus deployment (alarm size), the

availability of stairs and elevators, and automatic sprinkler

protection, on the time it takes to execute essential fireground

tasks and on the tenability inside a high­rise building, particularly

on the fire floor and floor above the fire. It is expected that the

results of this study will be used to evaluate and develop high­rise

related performance objectives in NFPA 1710.

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6. Experimental Methods
 

Planning for the field experiments was multifaceted. The

resources required to perform field tests representative of a

high­rise structure fire are numerous. Though grant

funding was necessary, the experiments required resources in

addition to the grant dollars available. Collaboration with subject

matter experts as well as several fire and rescue departments was

needed to assure the time­to­task portion of the experiments was

completed.

Subject matter experts (SMEs) were identified to assist principal

investigators in developing experiment protocols that would be

broadly applicable to the U.S. fire service. Industry experts

included metropolitan fire chiefs, metropolitan training officers,

textbook authors, and nationally renowned fire service leaders

with experience in high­rise firefighting.15

6.1 Scenarios

Based on SME input, including the fact that high­rise fires

represent an extraordinary challenge to fire departments,

scenarios were developed that included each variable in

combination with the others.Variables included four levels of

crew size (3­, 4­, 5­, and 6­person crews), two levels of alarm size

(high = 4 engines, 4 trucks, 2 battalion chiefs and 3

ambulances/low = 3 engines, 3 trucks, 2 battalion chiefs and 2

ambulances), and two methods of vertical ascent (stairs/elevator).

The various combinations of these variables resulted in 16

different scenarios, as shown in Table 1 below.

Each of the scenarios below involved a fire on the 10th floor of a

13 story building with an open floor plan configuration of 100 ft by

300 ft (30 m by 91 m), for an area of 30,000 sq ft (2800 m2). The

primary fuel load is open­wall cubicle material with typical desk

and drawers, computers, printers and office chairs. The scenarios

included two victims (always in the same location); one located on

the fire floor and one located on the floor above the fire (Floor 11).

Scenario 1: High­alarm assignment with 6­person crews

dispatched to the building. Two fire service access

elevators are available for fire service use. (Best case)

Scenario 2: Low­alarm assignment with 6­person crews

dispatched to the building. Two fire service access

elevators are available for fire service use.

Scenario 3: High­alarm assignment with 5­person crews

dispatched to the building. Two fire service access

elevators are available for fire service use.

Scenario 4: Low­alarm assignment with 5­person crews

dispatched to the building. Two fire service access

elevators are available for fire service use.

Scenario 5: High­alarm assignment with 4­person crews

dispatched to the building. Two fire service access

elevators are available for fire service use.

Scenario 6: Low­alarm assignment with 4­person crews

dispatched to the building. Two fire service access

elevators are available for fire service use.

Scenario 7: High­alarm assignment with 3­person crews

dispatched to the building. Two fire service access

elevators are available for fire service use.

Scenario 8: Low­alarm assignment with 3­person crews

dispatched to the building. Two fire service access

elevators are available for fire service use.

Scenario 9: High­alarm assignment with 6­person crews

dispatched to the building. Stairs are available for

fire service use.

Scenario 10: Low­alarm assignment with 6­person crews

dispatched to the building. Stairs are available for

fire service use.

Scenario 11: High­alarm assignment with 5­ person crews

dispatched to the building. Stairs are available for

fire service use.

Scenario 12: Low­alarm assignment with 5­person crews

dispatched to the building. Stairs are available for

fire service use.

Scenario 13: High­alarm assignment with 4­person crews

dispatched to the building. Stairs are available for

fire service use.

Scenario 14: Low­alarm assignment with 4­person crews

dispatched to the building. Stairs are available for

fire service use.

Scenario 15: High­alarm assignment with 3­person crews

dispatched to the building. Stairs are available for

fire service use.

Scenario 16: Low­alarm assignment with 3­person crews

dispatched to the building. Stairs are available for

fire service use. (Worst case)

Table 1: Sixteen unique experimental variations

15. Subject matter experts included Russ Sanders (NFPA, Louisville KY Chief, Retired), Dennis Compton (IFSTA, NFFF, Mesa, AZ Chief, Retired), Peter Van Dorpe

(Training Chief Chicago, IL), David Rohr, (Chief Fairfax City,VA, Fairfax County,VA Operations Chief, Retired),Vincent Dunn (Deputy Chief FDNY, Retired), Ben

Klaene (Cincinnati, OH Training Chief, Retired), James Walsh (Deputy Chief, Fairfax County,VA), Richard Bowers (Chief Montgomery County, MD) and Richard

Travers (Deputy Chief FDNY, Retired).

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Experimental protocols, following the Incident Command

System, were developed for each of the scenarios. Crew cue cards,

denoting each task expected to be performed by participants, were

prepared. (See Crew Cue Card examples in Appendix A.)

6.2 Participating Fire and Rescue Departments

In addition to the SME work, 13 Fire and Rescue Departments

in the Washington D.C. metropolitan area committed resources to

the experiments. The departments were all part of the

Metropolitan Washington Council of Governments Region.16

n Arlington County Fire Department
 

n Alexandria Fire Department
 

n Fairfax County Fire and Rescue
 

n Prince William County Fire and Rescue
 

n District of Columbia Fire Department
 

n Montgomery County Fire and Rescue
 

n Howard County Department of Fire and Rescue Services
 

n Fairfax City Fire and Rescue
 

n Prince George’s County Fire/EMS Department
 

n Loudoun County Fire and Rescue Department
 

n Metropolitan Washington Airport Authority
 

n Manassas City Fire and Rescue
 

n Stafford County Fire and Rescue
 

Departments committed both engine and truck crews and

equipment, as well as heavy rescue and Advanced Life Support

(ALS) ambulance crews and equipment. The daily number of

firefighters committed to the experiments varied from 72 to 136.

Participating departments used the experiments as intense

multi­unit training exercises in high­rise firefighting. Every

detailed task in the protocol used for the experiments provided an

opportunity to engage in actual and accurate high­rise fire

suppression and search and rescue operations.

6.3 Field Site

In addition to crew resources, a vacant high­rise building was

necessary. The search for a building began in the D.C.

Metropolitan area. Each Fire and Rescue Department committed

to the study searched their jurisdictions for available properties.

Department Fire Inspectors were particularly knowledgeable of

properties in their areas. The various property searches revealed

potential vacant properties in the Crystal City (Arlington

County),Virginia area. Due to BRAC17 activities, several buildings

in the area were vacant. Once vacant buildings were identified,

researchers worked with the local Fire and Rescue Department

Chief Officers to contact building owners/managers. Following

months of contacts and negotiation, a building was identified and

secured.Vornado/Charles E. Smith18 committed a vacant 13­story

high­rise structure located at 223 23rd Street, Crystal City,

Virginia to the experiments (Figure 1).

Figure 1: High-rise building located at 223 23rd Street, Crystal City, VA

16. The Metropolitan Washington Council of Governments (COG) is an independent, nonprofit association that brings area leaders together to address major regional

issues in the District of Columbia, suburban Maryland and Northern Virginia. COG’s membership is comprised of 300 elected officials from 22 local governments,

the Maryland and Virginia state legislatures, and U.S. Congress.

17. BRAC is the commonly used acronym for the formal name of the Defense Base Closure and Realignment Commission. The BRAC Commission was created to

provide an objective, thorough, accurate, and non­partisan review and analysis, through a process determined by law, of the list of bases and military installations

which the Department of Defense (DoD) has recommended be closed and/or realigned. The DoD list of recommendations was formally presented to the BRAC

Commission on May 13th, 2005. http://www.brac.gov/About.html

18. Vornado/Charles E. Smith is the Washington division of Vornado Realty Trust, a fully integrated Real Estate Investment Trust (NYSE:VNO). Recognized as the largest

owner/manager of commercial properties in the Washington D.C. region,Vornado/Charles E. Smith owns and manages 74 office properties containing 18 million

square feet and seven residential properties containing 2,424 units, primarily located in the District of Columbia and Northern Virginia.

30
                               

                                         

                           

                               

               

     

   

               

                   

           

             

                   

             

             

                   

                 

             

                 

               

       

             

                     

               

                 

                 

               

                 

                   

             

                 

               

                 

               

                     

                       

                     

                   

6.4 Site Preparation

Upon receiving access to the building, preparation began to

build props, as well as to ensure that elevators, electricity, and

other amenities were available for use.

Building elevators were evaluated, full weight­load tested, and

certified to ASME standards19 to ensure that they were safe for use

by study investigators and firefighters. Similarly, stairwells were

cleaned and secured for use in the study.

Since the simulated fire was located on the 10th floor, cubicles

were constructed to simulate the office environment of a typical

Washington D.C. area commercial office building. Cubicles were

built of plywood sheathing and 2x4 frames. The cubicle farm

provided a common, though complex, search for firefighters on

the fire floor (Figure 2).

In consultation with SME’s, search patterns were established

throughout both the 10th and 11th floor (the fire floor and floor

Figure 2: Office cubicle props on fire floor (10th)

Figure 3: Direction signage

above the fire). Directional signage was prepared and placed

throughout the building (examples shown in Figure 3) to ensure

crews moved in the same direction throughout the building while

completing assigned tasks. These efforts assured the replication of

each experiment in the same manner regardless of crew size,

alarm level, or mode of vertical ascent (the study variables).

Fire and smoke simulators (a non­toxic suspension consisting

primarily of propylene glycol) were acquired by the IAFF from

BullEx Inc.20 to provide realistic visibility conditions on Floors 10

and 11. BullEx provided both digital fire displays and smoke

generators necessary to simulate both heavy fire and smoke

conditions on the fire floor and heavy smoke on the floor above

the fire. The fire display and the smoke generator may be seen in

Figure 4 and the visibility resulting from heavy smoke is shown in

Figure 5. (See also Fire and Smoke Simulation, Section 6.6).

19. American Society of Mechanical Engineers (ASME) is a not­for­profit membership organization that enables collaboration, knowledge sharing, career enrichment,

and skills development across all engineering disciplines. ASME has over 600 technical standards improving the safety and efficiency of boilers, elevators, cranes,

nuclear energy, pipelines, and many other areas. ASME Standards are used in over 100 countries.

20. BullEx, Inc. is a technology company devoted to utilizing smart technology to develop life­saving products.

31
                   

               

             

                         

           

                     

                       

                       

                   

                   

                     

               

               

                 

                 

                         

               

                     

                   

                     

               

                   

               

                 

                 

               

                 

           

       

             

Due to the potential for building damage, crews could not flow

water in the high­rise structure,study investigators worked with

participating department training academies to develop a substitute

that would weigh and perform as closely as possible to a 2 1⁄2 inch

charged hose line. Montgomery County Training Academy

instructors prepared more than 600 ft (183 m) of sand­filled 2 1⁄2

inch hose lines. The hose lines were then separated into 200 ft (61

m) sections and capped on each end to contain the sand. The weight

of the sand­filled lines closely approximated that of a charged line.

The sand­filled lines also mimicked the movement of a charged line

except at 90o turns. Crews were instructed to be aware of the need

for proper hose handling as they advanced the lines.

Unfortunately, ceilings in the building could not be pulled

during each experiment to allow firefighters to check for fire

extension and then replaced for the next test. Therefore, pulley

systems were built on the fire floor and the floor above the fire to

simulate firefighters pulling ceiling tiles to check for fire

extension. Weights were connected to one end of the pulley and a

pike pole to the other end. Firefighters were instructed how many

pulls on the pike pole were required to complete the assigned task.

Electronic search markers were created to track firefighters on

the fire floor and the floor above the fire. NIST investigators

developed an electronic push­button system (see Figure 6) that

firefighters were to activate as they searched an area. These

buttons allowed researchers to record the precise time at which

firefighters reached various areas throughout these floors and are

discussed in greater detail in Sections 6.5 and 7.12.

Figure 4: Fire display and smoke generator Figure 5: Fire /smoke conditions on 10th floor

Figure 6: Electronic search marker

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Numbered wooden block markers were used on the floors

without smoke present (the 9th floor directly below the fire and

the upper floors above the 11th floor). Twenty blocks were

distributed throughout each of these floors in pre­determined

locations. Firefighters were instructed to collect the markers as

they searched and then to deliver the twenty markers to people

acting as timers on the floor to complete the search.

To ensure that there were sufficient SCBA cylinders for use in the

experiments, Arlington County Fire and Rescue shared a cache of

cylinders for the duration of the experiments. The cylinders were

used by the stairwell/elevator support crew to supply the staging

area and as extra cylinders that each firefighter took up with them

in their initial ascent.

To make certain that crews had the capability to communicate

without interruption, both Arlington County Fire and Rescue and

Fairfax County Fire and Rescue provided a radio cache for use by

the other fire departments throughout the study.

Finally, an experiment calendar was established and provided to

participating departments. The calendar reflected 64 experiments

to be conducted over 32 days (2 per day). All experiments were

performed between the dates of May 15 and July 13, 2012. The 64

tests were divided into 4 sets of 16 experiments to match the 16

scenarios noted previously. The first set of 16 experiments was

used as “shake­down” tests to refine the study protocols, timers,

and building preparation. The remaining 48 experiments were

carefully deployed for data collection, analysis, and reporting.

6.5 Instrumentation

Heavy smoke conditions present on the fire floor and the floor

above the fire posed a significant problem for tracking firefighter

crew tasks. In order to track the fire crews through these

conditions, a recording system consisting of 46 momentary

switches were installed throughout the two floors. Twenty­four

were installed on the fire floor and 22 on the floor above. These

buttons were positioned such that they could capture the time

signal for critical events such as time of victim rescue and time

when search and rescue operations were completed.

The momentary buttons were large red arcade­style momentary

switches mounted onto wooden platforms (as shown in Figure 6).

The button assemblies were securely fastened onto interior walls

of cubicles and offices. As firefighters were searching, they were

instructed to press and momentarily hold the buttons. When

pressed the buttons sent a signal to the data acquisition system

located on the floor above the fire.

All 46 buttons were hardwired via four conductor telephone

wires to the data acquisition system. The data acquisition system

(DAQ) used for the buttons consisted of:

n 2 x Thermocouple­2095 32­Ch Terminal Block

n SCXI­1000 4 Slot Chassis

n 2 x National Instruments SCXI­1102 32­Ch Thermocouple

Input Amplifier

n National Instruments SCXI­1600 USB Data Acquisition and

Control Module

When a button was pressed, a signal traveled through the DAQ

system and created a timestamp. These timestamps were recorded

onto a laptop and stored for later analysis. The information

gathered from the buttons is presented later in the report.

6.6 Fire and Smoke Simulation

Due to the need for repeatability over the course of two months

and the inability to ignite a fire within the high­rise building, fire

and smoke simulators were used. On the fire floor, 5 BullEx

Smart­Eye fire displays were coupled with 5 BullEx 3000 smoke

generators. The smoke generators were tied to the fire displays

such that the amount of smoke created and the size of the fire

displayed followed the simulated fire model. The displays and

smoke generators also reflected the impact of fire suppression by

firefighters. When firefighters accomplished the corresponding

task, the displays initialized a ramp­down feature and eventually

turned off. As with a real fire, when the fire was completely

extinguished, visibility conditions on the floor began to improve.

More details about how the simulated fires were created can be

found in Section 6.4 on Site Preparation. On the floor above the

fire (Floor 11) one BullEx 3000 smoke generator was installed to

simulate smoke movement through the high­rise.

6.7 Safety Protocols

Firefighter safety was a primary concern in conducting the

high­rise field research. The fire departments participating in this

study regularly conduct fire and rescue training for their staff and

recruits compliant with NFPA and other industry standards and

practices.

Safety Personnel

A Safety Officer was assigned to the experiments each day to

assure compliance with NFPA standards. This position was filled

primarily by a designated safety officer from the Howard County

Fire and Rescue Department. The Safety Officer (Figure 7)

participated in all crew orientation activities and daily briefings,

and was actively involved in overseeing all experiments. The

Safety Officer had full access to all floors of operation and had full

authority to terminate any operation if any safety violation was

observed.

Figure 7: Safety officer

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In addition to the safety officer, the rapid intervention crew

deployed within the experiments also functioned as a real RIC

unit, available and expected to respond in the event of an actual

firefighter health or safety emergency. Ambulance 1, operating the

rehabilitation area in the experiments, was always staffed with a

fully equipped 2­person Advanced Life Support (ALS) crew,

which was also expected to respond in the event of an actual

emergency. Finally, a dedicated ALS­staffed ambulance, not taking

part in the actual experiment, was on standby at the site for all

experiments.

During each morning orientation, crews were provided a radio

code (“code blue”) for signaling that a firefighter needed to drop

out of the exercise for any reason. Interoperable radio

communication was always available during the experiments for

command and tactical operations and was also to be used should

a code blue arise. Experiments were stopped for any action

considered to be a protocol breach or safety concern.

In addition to the resources mentioned previously, researchers

and timers were used for oversight and accountability for each

experiment. Experimental protocols and methods were designed

to assure the most controllable, safe, yet realistic high­rise fire

environment possible.

On air time

Another safety protocol limited crews to 15 min ‘on air’ time

for completing tasks. It was determined that 15 min was a

reasonable lower bound for a firefighter using a 30­minute

cylinder (despite performing similar tasks, some firefighters

consume air faster than others depending upon several factors,

such as physical fitness or stress level). Restaurant­style timers

with vibration and flashing red lights were used to page crews

when their ‘on air’ time reached 15 min. Upon receiving the

page or upon task completion, crew officers radioed division

supervisors or Incident Command (IC) to request dispatch of a

relief crew. Once relieved, the crews reported to the

rehabilitation area located adjacent to the staging area on the 8th

floor for a mandatory recovery period.

Air cylinders were refilled or replaced between experiments as

needed and at the end of the test day to ensure crews were

equipped to return to duty.

Rehab

A closely related priority was adequate rehabilitation. Adequate

rehab was necessary to ensure firefighter safety and readiness to

repeat experiments with equivalent performance. NFPA 1584®

Standard on the Rehabilitation Process for Members During

Emergency Operations and Training Exercises (NFPA 1584)21

expresses three stages of rehabilitation: preparedness, incident

scene and training rehabilitation, and post­incident

rehabilitation. The crew hold area (lobby level), the front of the

building (shaded from sun), and the staging/rehab area on the

8th floor were cooled for crew rest and rehabilitation.

Throughout the experiments, as in a real fire event, food, water

and electrolyte­rich drinks were available for crew intake. The

importance of staying well­hydrated before, during and after the

experiments was especially emphasized (Figure 8 to Figure 10).

Figure 8: Crew rehab — Crew hold area

Figure 9: Crew rehab — Front of building Figure 10: Crew rehab — 8th floor

21. NFPA Standard 1584: Recommended Practice on the Rehabilitation of Members Operating at Incident Scene Operations and Training Exercise provides

comprehensive guidelines on developing rehab SOPs and performing the duties during emergency operations and training exercises.

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7. Time­to­Task Experiments
 

7.1 On­Scene Fire Department Tasks

The on­scene fire department time­to­task piece of the high­rise

study focused on the tasks firefighters perform after they arrive on

the scene of a high hazard commercial structure fire. A number of

nationally recognized fire service subject matter experts were

consulted during the development of the on­scene fire

department tasks in order to ensure the broad applicability and

appropriateness of the task distribution. Forty­eight total

experiments were conducted to assess the time it took various

crew sizes to complete the same tasks on technically similar fires

in the same structure. The experiments compared the time to

complete key tasks during a typical high­rise firefighting scenario

using 3­, 4­, 5­, and 6­person crews. In addition to crew size, the

experiments assessed the effects of alarm assignment (high vs.

low) and vertical ascent mode (stairs vs. elevators). Therefore, 16

unique experiments (4×2×2 = 16) were conducted in triplicate,

totaling 48 (16×3) tests, as shown in the full replicate block in

Table 1. A full replicate was completed in a randomized order

(determined by randomization software) before a test

configuration was repeated.

7.2 Determination of Full­Alarm Assignment

Fire departments deploy different numbers of apparatus to

otherwise similar calls (often referred to as a full­alarm

assignment). These differences reflect deployment decisions made

at the department or community level. In order to best inform

decision­making about response to high­rise building fires,

full­alarm assignment configurations were gathered from

metropolitan fire departments throughout the U.S. and Canada.

As a pattern emerged, researchers were able to establish a low and

high alarm sequence, included in the study as a primary variable

named low/high alarm. Low alarm assignments consisted of 3

Engines, 3 Trucks, 2 Battalion Chiefs (with Aides), and 2

Ambulances. High alarm assignments consisted of 4 Engines, 4

Trucks, 2 Battalion Chiefs (with Aides), and 3 Ambulances.

7.3 Crew Size

For each experiment, the crew sizes studied included 3­, 4­, 5­,

and 6­person crews assigned to each engine and truck dispatched.

Crew sizes reflect the members of the crew, both officers and

firefighters, who actually engaged in completing tasks. In many

departments, company officers are primarily responsible for crew

command, crew safety, crew accountability, and communication

with other operating units on scene, along with the IC. These

officers do not directly engage in stretching hose lines, advancing

and operating hose streams, normal truck operations including

ventilation, or related tasks so that they can be available to focus on

crew command, situational awareness and crew accountability.

However, officers will assist in conducting searches and removing

victims when necessary. These officer tasks are essential to

firefighter safety, since studies show that situational awareness and

human error are contributing factors in nearly 20 % of the

fireground line­of­duty deaths, and that 40 % of firefighter injuries

are attributed to situational awareness (Moore, 2006, 2008).

During the experiments, however, the researchers, timers, and

safety officers fulfilled this officer role to assure safe tactical

practices and protocol compliance. Further, during the planning

stages of the experiments, it was determined that these officer

tasks could not be effectively measured with the experimental

methods used. Therefore, any department in which company

officers operate in a safety/accountability role as described should

consider the results and conclusions of this study as pertinent to

firefighter task performance only.

7.4 Number of Firefighters in the Experiments

For each experiment, the number of firefighters was determined

by the number of crew per apparatus, as the size of the full­alarm

assignment was held constant for the experiments.22 Table 2

shows the total number of firefighters actually deployed for each

of the 16 unique experimental configurations. The actual number

of firefighters used in the experiments is fewer than the total

calculated based on crew size and alarm size as described. This

difference is due to the fact that later arriving crews on the high

alarm deployment would have been assigned to base as tactical

reserve for use in later tasks. Since individual experiments were

stopped following the completion of a primary search and the

rescue of victims on the fire floor and the floor above the fire,

these resources weren’t filled during the exercise. Unlike the field

experiments, an actual high­rise fire would have engaged these

additional resources to conduct secondary search, overhaul, and

salvage.

22. Note that the on­scene staffing totals account for only the personnel assigned to “work” the fire. As previously explained, additional personnel were provided such as a

staffed on­site medic and a safety officer specific to the experiments. They are not included in the staffing described here.

35
             

               

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Vertical Ascent

Mode

Crew Si e Si e of Full*

Alarm

FFs

Engines/Trucks

FFs

3 BCs/Aides

and 3 Ambs

Total Number

of FFs**

Stairs 3 Low 54 12 66

Stairs 3 High 54 12 66

Stairs 4 Low 72 12 84

Stairs 4 High 72 12 84

Stairs 5 Low 90 12 102

Stairs 5 High 90 12 102

Stairs 6 Low 108 12 120

Stairs 6 High 108 12 120

Elevators 3 Low 54 12 66

Elevators 3 High 54 12 66

Elevators 4 Low 72 12 84

Elevators 4 High 72 12 84

Elevators 5 Low 90 12 102

Elevators 5 High 90 12 102

Elevators 6 Low 108 12 120

Elevators 6 High 108 12 120

Table 2: Actual crew size for each experiment

* Low Alarm Threshold is 3 Engines, 3 Trucks, 2 Battalion Chiefs (with Aides), 2 Ambulances

High Alarm Threshold is 4 Engines, 4 Trucks, 2 Battalion Chiefs (with Aides), 3 Ambulances

** Firefighter count does not include experimental staff or support personnel, such as the safety officer and stand­by EMS crew.

7.5 Department Participation

The training exercises were conducted in Arlington County,VA at

a 13 story commercial structure located at 223 23rd Street, Crystal

City during the months of May through July 2012. All training

took place in daylight between 8:00 am and 3:00 pm. Training was

postponed for extreme heat and rescheduled for a later date

following other scheduled experiments.

Participating departments considered the high­rise experiments

a prime opportunity for incident command, company officer and

firefighter training, as well as an opportunity for responding with

neighboring jurisdictions to a multi­unit drill in a high hazard yet

controlled environment. These departments committed a cache of

engines, trucks, heavy rescues, ambulances, and battalion chiefs to

the experiments. Some departments sent personnel separate from

apparatus to ensure that sufficient numbers of firefighters and

officers were available to conduct the training without depleting

on­duty resources. Battalion chiefs alternated between the roles of

Incident Commander, Division 10 (fire floor) and Division 11

(floor above the fire) supervisors. Figures 11 and 12 illustrate the

scale of participation in the training.

Figure 11: Apparatus parking on site Figure 12: Crew resources

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All firefighters and officers were oriented to the experiments and

the experimental response protocol each morning. Crews that

normally operated together as a company were kept intact to

assure typical operation for the crew during the scenarios.

Firefighters were added to or subtracted from crews based on the

protocol performed. Crews were regularly combined on the spot

and expected to perform as they would on any multi­unit

response to a high hazard structure fire.

The allocation of resources by the participating departments

made it possible to conduct back­to­back experiments each day

by rotating firefighters between more labor intensive tasks, less

intensive tasks and the rehabilitation areas.

7.6 Officer and Crew Orientation

All firefighters were required to attend an orientation each day

prior to the beginning of the experiments (see Figure 13). The

orientations were used to explain the purpose of the experiments,

experimental procedures, task flow, division of labor between

crews, radio communication, and milestone events in the scenario.

Daily orientations were conducted to assure that every study

participant attended at least one session. Orientations included a

description of the overall study objectives and the actual

experiments in which they would be involved. Even though no

live fire was used, the experiments were conducted consistent with

the requirements of NFPA 1403®: Standard on Live Fire Training

Evolutions (NFPA 1403)23. Full disclosure regarding the structure,

the simulated fire and smoke, and the tasks to be completed was

provided. Crews were also oriented to the fireground props, the

instrumentation used for data collection, and the specific

scenarios to be conducted. Every crew officer, Incident

Commander, and Division Supervisor was provided a

walkthrough of the structure during the daily orientation prior to

the start of the experiments (Figure 14). Figures 15 through 27

show firefighters performing some of the tasks that were

measured in the experiments.

Figure 13: Daily crew orientation Figure 14: Officer walkthrough

Figure 15: First Engine connects to hydrant Figure 16: Driver connects to Siamese

23. NFPA 1403 contains the minimum requirements for training all fire suppression personnel engaged in firefighting operations under live fire conditions.

37
           

                     

                               

         

Figure 17: Crews arrive in lobby

Figure 18: Crews ascend via stairs Figure 19: Crews ascend via elevator

Figure 20: Firefighters assist in moving the attack line Figure 21: Establish line above the fire (Floor 11)

and second line on Fire Floor

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Figure 22: Search crew proceeds to fire floor Figure 23: Search and rescue — Fire floor

Figure 24: Search and rescue — Floor above fire Figure 25: Victim located on floor above fire

Figure 27: Victim removed from building

Figure 26: Victim descends via stairs

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Each task was assigned a standardized start and end marker for end time for victim rescue was ‘removal of the victim to the 8th

consistent data recording. For example, search and rescue start floor stairwell landing’. The 38 tasks, including start and stop time

time was ‘initial crew entry onto a floor to begin a search’ and the markers, are shown in Table 3.

Table 3: Tasks and Measurement Parameters

Tasks Measurement Parameters Tasks Measurement Parameters

1. Initial Si e-up START> First Crew Goes to Work 15. Second Line-Connect to START> Crew ascends from lobby

STOP> Officer begins command Standpipe STOP> Second line connected to

statement on scene wye valve

2. Establish Command START> First Crew Goes to Work 16. Advance Second Line START> Second line no le

STOP> Command statement through 10th floor stairwell door

completed STOP> Second line-Water on Fire

3. Lobby Control START> First Crew Goes to Work 17. Fire Out START> Attack line no le

STOP> Attack/Evac through 10th floor stairwell door

stairwells/elevators are located, STOP> Attack and second lines

designated, and confirmed cross target threshold

4. Establish IRIC TIME> 2 crew members 18. Check for Fire Extension START> Firefighter(s) touch pike pole

assembled on 8th floor, not on on 10th floor STOP> Thirty pulls on weighted

air, standing by and ready to assist pike pole completed

in the event of firefighter

emergency 19. Positive Pressure TIME> 1 min after Fire Out

Ventilation-Fans

5. Establish RIC (RIT) START> Crew enters

stairwell/elevator from lobby 20. Roof Ventilation TIME> 1 min after Fire Out

STOP> Crew assembled on 8th

floor landing 21. Search and Rescue Crew START> Crew enters

Ascension (Floor 10) stairwell/elevator from lobby

6. Establish Medical, START> Initial arrival,Ambulance 1 STOP> Crew assembled on 8th

Rehab- Ambulance 1 START> Initial arrival,Ambulance 1 floor landing

STOP> Crew enters staging with

all equipment 22. Search and Rescue (Floor 10) START> Crew through 10th floor

stairwell door

7. Establish Medical, Ambulance-2 START> Initial arrival,Ambulance 2 STOP> Primary search on 10th

STOP> Crew enters staging with floor completed

all equipment

23. Victim #1 Found (Floor 10) START> Crew through 10th floor

8. Establish Medical, Ambulance-3 START> Initial arrival,Ambulance 3 stairwell door

STOP> Crew enters staging with STOP> Victim found on 10th floor

all equipment

24. Victim #1 Rescue (Floor 10) START> Victim found on 10th floor

9. Establish Staging START> Initial arrival, Truck 3 STOP> Victim arrives on 8th floor

STOP> Crew enters staging landing

10. Establish Stairwell/Elevator START> Initial arrival, Truck 5 25. Victim #1 Descent START> Victim exits 8th floor

Support STOP> 35 cylinders, extra search STOP> Victim exits building

rope and 2 coolers brought to

staging 26. LineAbove Fire CrewAscension START> Crew enters

stairwell/elevator from lobby

11. Attack Crew Ascension START> Crew enters STOP> Crew assembled on 8th

stairwell/elevator from lobby floor landing

STOP> Crew assembled on 8th

floor landing 27. Line Above Fire-Connect START> Crew ascends from lobby

to Standpipe

12. Attack Line-Connect to START> Crew enters STOP> Line above fire connected

Standpipe stairwell/elevator from lobby to wye valve

STOP> Attack line connected to

gated wye valve 28. Advance Line Above Fire START> Line above fire no le

through 11th floor stairwell door

13. Advance Attack Line START> Attack line no le STOP> Line above fire at target

through 10th floor stairwell door threshold

STOP> Attack line-Water on Fire

29. Check for Fire Extension START> Firefighter(s) touch

14. Second Line Crew Ascension START> Crew enters on 11th floor weighted pike pole

stairwell/elevator from lobby STOP> Thirty pulls on pike pole

STOP> Crew assembled on 8th completed

floor landing

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Tasks Measurement Parameters Tasks Measurement Parameters

30. Search and Rescue Crew

Ascension (Floor 11)

START> Crew enters

stairwell/elevator from lobby

STOP> Crew assembled on 8th

floor landing

35. Search and Rescue

(Upper Floor) Crew Ascension

START> Crew enters

stairwell/elevator from lobby

STOP> Crew assembled on 8th

floor landing

31. Search and Rescue (Floor 11) START> Crew through 11th floor

stairwell door

STOP> Primary search on 11th

floor completed

36. Search and Rescue

(Upper Floor)

START> Crew through upper

floor stairwell door

STOP> Search completed (must

have all 20 prop markers)

32. Victim #2 Found (Floor 11)

33. Victim #2 Rescue (Floor 11)

34. Victim #2 Descent

START> Crew through 11th floor

stairwell door

STOP> Victim found on 11th floor

START> Victim found on 11th

floor

STOP> Victim arrives on 8th floor

landing

START> Victim exits 8th floor

STOP> Victim exits building

37. Search and Rescue Crew

Ascension (Floor 9)

38. Search and Rescue (Floor 9)

START> Crew enters

stairwell/elevator from lobby

STOP> Crew assembled on 8th

floor landing

START> Crew through 9th floor

stairwell door

STOP> Search completed (must

have all 20 prop markers)

7.7 Other Tasks

Similar to the residential fireground study (Averill et al., 2010),

some fireground tasks were not included in the scope of this study.

These include salvage and overhaul, mitigation of water, and removal

of firefighting equipment from the building to the fire apparatus.

From the time when the key tasks measured by this study have been

completed to the point at which units dispatched to the incident can

be returned to service may be a considerable period of time. This

time period affects the delivery of fire department services since units

are not available to respond to simultaneous incidents, and it should

be accounted for in the design of community standards of cover.

7.8 Data Collection: Standardized Control Measures

Several measures were used to collect data, including radio

communications, task timers, search buttons, and a number of

video recordings. Performance was timed for each task in each

scenario including selected critical tasks such as Water on Fire,

Fire Out, Search Complete,Victim Found, and Victim Rescue.

Data were collected for crew performance on each task. Individual

firefighter time was not considered.

7.9 Task Flow Charts and Crew Cue Cards

As for the residential fireground experiments (Averill et al.,

2010), task procedures were standardized for each scenario. Task

flow charts were created and then customized for the various crew

sizes. The carefully designed task flow ensured that the same

overall workload was maintained in each experiment but was

redistributed based on the number of personnel available to do

the work. See Appendix A for a full description of tasks for each

scenario.

All tasks were included in each scenario, and cue cards were

developed for each individual participant in each scenario. For

example, a 4­person crew would have a cue card for each person

on the crew, including the officer, the driver, and the two

firefighters. As illustrated in Figure 28, cards were color­coded by

crew size to assure proper use in each scenario.

Figure 28: Crew cue cards

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7.10 Radio Communications

Interoperability and intraoperability of radio equipment used

by all participating departments made it possible to use regular

duty radios for communication during the experiments.

Company officers were instructed to use radios as they would in

an actual incident while keeping unnecessary radio traffic to a

minimum.

Arlington County Fire and Rescue Communications recorded all

radio interaction as a means of data backup. Arlington County

Communications assigned the study two exclusive channels. One

channel was used by the researchers for starting, monitoring, and

stopping each experiment while the other was designated the

tactical command channel for use by study participants. Once all

data quality control measures were complete, the

communications records were overwritten as a routine procedure.

7.11 Task Timers

Eleven observers/timers, trained in the use of a standard stop watch

with split­time feature,recorded time­to­task data for each field

experiment, as shown in Figure 29. To ensure understanding of the

observed tasks, firefighters were used as timers. Each timer was

assigned specific tasks to observe and to record the start and end

times.All timers wore high­visibility safety gear on the fireground.

To enhance accuracy and consistency in recording times, the

data recording sheets used color­coding for the tasks (see

Appendix A). Each timer was assigned tasks coded in the same

color. Due to the large number of firefighters participating in the

experiments, crews wore color­coded “marker bands” around

their SCBA bottles, as shown in Figure 30. These bands were

coded to match specific categories of tasks corresponding with the

timer data sheets and assisted the timers in identifying which

crews performed tasks they were assigned to observe.

Figure 29: Task timers located throughout the high­rise structure

Figure 30: Task marker bands worn by firefighters during the experiments

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Timers/observers were also used for purposes of quality control

and safety. They were allowed to direct crews and answer

questions, as long as the experiment protocol was not affected.

This local oversight was necessary since crews were working on

several different floors simultaneously.

Timers were stationed on different floors in various parts of the

building; therefore they were issued radios to allow them to hear

the experiment “start time” and “stop time” commands and to

maintain contact with the lead investigators in the event that there

was a protocol breach or safety concern.

7.12 Search Buttons

Heavy smoke conditions on the fire floor and floor above

prevented accurate tracking of search and rescue operations with

timers. Instead, buttons were distributed at fixed locations on

both floors. Firefighters performing searches were instructed to

press the buttons as they encountered them along the prescribed

search paths. When a button was pressed, the time of the press

was recorded through a data acquisition system. From the

locations of the buttons and the time each was pressed, a history

of search and rescue progress on both floors was generated. This

included Victim Rescue time (a button was located at the victim

location) and Search Complete time (a button was located at the

end of the search). Since the floor layouts of the fire floor and the

floor above were different, the button placement on each floor

was unique.

On the fire floor, 24 buttons were installed in the cubicles, nine

buttons on the inside search loop and 15 buttons on the outside

search loop. Figure 31 shows an isometric view of the fire floor

with the location of each button marked. The image was created

using Smokeview, a software tool developed by NIST to visualize

FDS results. The victim was located at button 18.

Figure 31: Search button locations on the fire floor

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On the floor above the fire (Floor 11), there were 22 buttons situated the open­floor plan arrangement of Floor 10.As a result, buttons

as shown in Figure 32. The conventional office configuration of were installed along the walls of offices and connecting hallways. The

Floor 11 (with floor to ceiling partitions) was quite different from victim on Floor 11 was located at button 15.

Figure 32: Search button locations on the floor above the fire (floor 11)

7.13 Video Records

In addition to the timers, video documentation was taken on

one full set of high­rise scenarios. These video recordings

provided a backup for timed tasks and for quality control. No

fewer than six cameras were used to record fireground activity

from varied vantage points.Video records were available for use

in the data quality control process.

7.14 Crew Assignments

Crews from each participant department that regularly operated

together were assigned to work as either engine or truck

companies in each scenario. Depending on the scenario (crew size

of 3, 4, 5, or 6), firefighters were added or subtracted from

regularly assigned crews to assemble the appropriate number for

the scenario. This exercise, along with assigning different crews

from different shifts and stations to the study on a daily basis,

reduced learning from exact repetition of the same task and

provided an opportunity for firefighters and officers from

multiple departments to train for working together in a high

hazard/ high risk environment.

Additionally, crews assigned to each responding company

position in one scenario were assigned to another responding

company position in subsequent scenarios, with the objective of

minimizing learning from one experiment to another. For

example, crews in the role of Engine 1 in a morning scenario

might be assigned to the Engine 7 position in the afternoon.

7.15 Response Time Assumptions

Response time assumptions were made based on time objectives

set forth in NFPA 1710, which is the nationally recognized

consensus standard for career firefighter deployment and includes

requirements for fire department arrival time, staffing levels, and

fireground responsibilities.

In addition to the travel time and crew assembly time, the

overall response time to a structure fire includes fire ignition,

recognition, call to 9­1­1, call processing, dispatch, and turnout of

responding crews. The various time segments assigned to the

values in the overall response time were based on NFPA 1710 and

NFPA 1221®.24

24. NFPA 1710® Organization and Deployment of Fire Suppression Operations, Emergency Medical Operations, and Special Operations to the Public by Career Fire Departments.

4.1.2.1 The fire department shall establish the following objectives:(1) Alarm handling time to be completed in accordance with 4.1.2.3.(2) 80 s for turnout time for fire and

special operations response and 60 s turnout time for EMS response

4.1.2.3 Alarm Handling.

4.1.2.3.1 The fire department shall establish a performance objective of having an alarm answering time of not more than 15 s for at least 95 % of the alarms received and not

more than 40 s for at least 99 % of the alarms received, as specified by NFPA 1221.

4.1.2.3.2 When the alarm isreceived at a public safety answering point(PSAP) and transferred to a secondary answering point or communication center,the agency responsible

forthe PSAP shall establish a performance objective of having an alarm transfertime of not more than 30 s for at least 95 % of all alarms processed, as specified by

NFPA 1221.

4.1.2.3.3 The fire department shall establish a performance objective of having an alarm processing time of not more than 60 s for at least 90 % of the alarms and not more

than 90 s for at least 99 % of the alarms, as specified by NFPA 1221.

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Additional time segments included in

overall response time

1) Fire ignition = time ero

2) 30 s for recognition (detection of fire) and call to 9-1-1

3) 60 s for call processing/dispatch

4) 80 s for turnout

participating department station/company locations. The

software was then used to map the response (travel time) of the

appropriate companies to the scene.

After on­scene arrival, the ‘time to engagement’ or ‘time to

intervention’ to stop the fire must be considered. This time period

is referred to as ‘assembly time’, which is measured from the time

apparatus wheels stop at the scene and includes the time for

firefighters to gather equipment from the apparatus and the time

for firefighters to walk to the building, get an assignment, and

enter the building. To account for this additional time to

intervention, 90 s was added to the travel time for each company.

Therefore, the total time including detection, call processing,

turnout, and travel time plus the on­scene assembly time is

referred to here as the ‘go­to­work’ time. Figure 33 shows the

measurement of time from fire ignition through the response and

performance times to the completion of all firefighting tasks.

These time segments were added to the overall response time

and considered in both time­to­task data analysis and fire

modeling.

Responding company on­scene arrival times were calculated

using ArcGIS (ArcInfo) geographical information system (GIS)

software25 used for modeling emergency response. The address of

the study location was entered into the GIS system along with all

Figure 33: Timing for firefighter response and performance

4.1.2.4 The fire department shall establish a performance objective of not less than 90 % for the achievement of each turnout time and travel time objective specified in 4.1.2.1.

25. Geographic information system (GIS) software lets users visualize, question, analyze, interpret, and understand geographical data to reveal relationships, patterns, and trends.

GIS mapping software has a routing feature that projects travel times to a specific address from various multiple locations. GIS not only records travel time but also records the

order of arrival of apparatus traveling to the address based on their origin.

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Table 4 shows the go­to­work time of responding units

according to alarm size. The routes taken by the responding units

are shown in the map in Figure 34. As noted previously in Table 2,

the actual number of firefighters used in the experiments was

fewer than the total calculated based on crew size and alarm size.

This difference is due to the fact that later arriving crews on the

high alarm deployment would have been assigned to base as

tactical reserve for use in later tasks. Since individual experiments

were ended following the completion of a primary search and the

rescue of victims on the fire floor and the floor above the fire,

these resources weren’t used during the exercise. Unlike the field

experiments, an actual high­rise fire would have engaged these

additional resources to conduct search, overhaul, and salvage.

HIGH LOW HIGH LOW

Engine 1 7:34 Engine 1 7:34 Ambulance 7* 16:00 BC 3 16:00

Truck 1 7:34 Truck 1 7:34 BC 3 16:00 Truck 5 16:05

Ambulance 1 7:34 Ambulance 1 7:34 Truck 5 16:05 Engine 9 16:17

Engine 2 9:03 Engine 2 9:03 Ambulance 8* 16:05 BC 4* 16:17

Ambulance 2 10:20 Ambulance 2 10:20 Engine 9 16:17 Truck 6 16:51

Engine 3 11:01 Engine 3 11:01 Ambulance 9* 16:17 BC 5* 16:51

Truck 2 11:01 Truck 2 11:01 BC 4* 16:17 Truck 7 17:02

Ambulance 3 11:01 BC 1 11:01 Engine 10* 16:29 Truck 8 17:14

BC 1 11:01 Truck 3 11:58 Engine 11* 16:41 Truck 9 17:32

Engine 4 11:58 BC 2 12:35 Engine 12* 16:43 BC 6* 18:26

Truck 3 11:58 Ambulance 3 14:11 Truck 6 16:51

Truck 4 12:17 Engine 4 15:08 BC 5* 16:51

BC 2 12:35 Engine 5 15:27 Truck 7 17:02

Engine 5 15:27 Truck 4 15:27 Truck 8 17:14

Ambulance 4* 15:27 Ambulance 4* 15:27 Truck 9 17:32

Engine 6 15:45 Engine 6 15:45 Truck 10* 18:21

Ambulance 5* 15:45 Engine 7 15:45 BC 6* 18:26

Engine 7 15:45 Ambulance 5* 15:45 Truck 11* 18:52

Ambulance 6* 15:45 Ambulance 6* 15:45 Truck 12* 19:25

Engine 8 16:00 Engine 8 16:00 *not actually dispatched during experiments

Table 4: Go­to­work times calculated by GIS

46
                   

Created using ESRI ArcGIS software and TeleAtlas Geographic Data both licensed to the IAFF.

Figure 34: Route from each fire station to the fire location

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8. Stages of High­Rise Fire Operations
 

The on­scene fire department task stage of the study focused on

the tasks firefighters perform after they arrive on the scene of a

high­hazard high­rise residential structure fire.A number of

nationally recognized fire service experts were consulted during the

development of the on­scene fire department tasks in order to ensure

broad applicability and appropriateness of the task distribution.26

8.1 Incident Command

The high­rise fireground operations were managed and controlled

using the Incident Command System (ICS).27 For each experiment,

the officer on the first arriving company assumed Incident

Command (IC). The officer maintained command until the arrival

of the first Battalion Chief, at which time IC was transferred to the

chief and the company officer assumed Lobby Control. Upon

assuming command, the first Battalion Chief established the

incident command post from his vehicle located in the front of the

building, as shown in Figure 35.After assuming command, the IC

confirmed the location and tasks of all companies that arrived prior

to arrival.All subsequent crews entering the structure/fireground

passed by the IC to check in and receive their assignments.

It was the responsibility of the IC to design and implement a

basic fireground strategy, maintain overall situation awareness of

progress toward critical objectives, and manage all equipment,

personnel, procedures and communications operating within the

high­rise structure. In order to manage the numerous assets, the

IC and aide used a command board (shown in Figure 36). The

chief’s aide maintained the board while the IC maintained

command via radio communication.

Upon arrival of Battalion Chief (BC) Two and Battalion Chief

Three, the IC assigned them to supervise operations on the fire

floor (10th floor) and the next most hazardous floor, the floor

above the fire (11th floor). These two BC’s became Division 10

and Division 11, respectively. All crews operating on these two

floors then communicated directly with their respective division

commander, who in turn communicated with the IC. Necessary

communications included company task status, on­air supply

status, and any necessary firefighter safety interaction. If crews

operating in Division 10 or Division 11 required relief prior to

task completion, relief was requested to the Division Supervisor.

Request for relief crews were relayed from Division Supervisors to

the IC then to the staging manager. The staging manager sent

fresh crews to their assignments as instructed by the IC. All

relieved crews were sent from their task area to Rehab (8th floor)

for a minimum recuperation period of 15 min.

Figure 35: Incident Command post

Figure 36: Incident Command board

26. Subject matter expertsincluded Russ Sanders(NFPA, Louisville KY Chief,Retired),Dennis Compton (IFSTA,NFFF,Mesa,AZ Chief,Retired),PeterVan Dorpe (Training Chief

Chicago,IL),David Rohr,(Chief Fairfax City,VA, Fairfax County,VA Operations Chief,Retired),Vincent Dunn (Deputy Chief FDNY,Retired),Ben Klaene (Cincinnati,OH

Training Chief,Retired),JamesWalsh (Deputy Chief, Fairfax County,VA),Richard Bowers(Chief Montgomery County,MD) and Richard Travers(Deputy Chief FDNY,Retired).

27.The Incident Command System (ICS)is a standardized, on­scene, all­hazards incident management approach that allows forthe integration of facilities, equipment, personnel,

procedures, and communications operating within a common organizational structure.ICS also enables a coordinated response among various jurisdictions and functional

agencies, both public and private, and establishes common processes for planning and managing resources.ICS is flexible and can be used forincidents of any type,scope, and

complexity.ICS allows its users to adopt an integrated organizational structure to match the complexities and demands of single or multiple incidents.

http://www.fema.gov/incident­command­system,January 2013.

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During the experiments, participating departments used the IC

position as an intense training opportunity for their Battalion

Chiefs, as well as those in line for promotion to that position. The

high­rise structure fire experiments also provided the opportunity

for multi­jurisdictional interaction for crews with command

officers from nearby departments.

8.2 Lobby Operations

Lobby Control

The IC assigned an officer or firefighter to establish Lobby

Control to provide critical intelligence, establish accountability,

and control the building systems. Due to the dynamic nature of a

high­rise event, the Lobby Control Officer must multi­task. Lobby

Control was responsible for duties related to managing the

stairwells, elevators, and the HVAC systems (see Figures 37 and

38). The duties of Lobby Control included the following.

n Consulting with the building engineer to determine the

presence and status of all key building systems, as well as any

information about the status and nature of the fire

n Controlling or shutting down the HVAC system after

consulting with the IC

n Assisting incident command post operations

n Locating all interior stairs.

n Preventing all building occupants and nonemergency

personnel from entering the building

n Controlling, operating, and accounting for all elevators

n Directing incoming companies to the proper elevator or

stairwell

Controlling the elevators and stairwells is the only way to

effectively gain access to the upper floors of a high­rise building.

Another important Lobby Control duty is to gain control of the

HVAC system. If operated properly, the HVAC system can prevent

heat, smoke, and toxic gases from spreading throughout the

building and reaching more occupants than might otherwise be

exposed. Conversely, if operated incorrectly, the HVAC system

may spread the products of combustion well beyond the

immediate fire area and into other occupied areas.

Throughout the experiments, Lobby Control was established by

the officer or firefighter remaining in the lobby from the first

arriving engine company. The position was then supplemented by

the assigned crew upon arrival. As in an actual incident, all

Figure 37: Lobby Control / Accountability

Figure 38: Lobby Control / Elevator access

incoming crews were required to stop at Lobby Control to

confirm the location of the fire floor, staging floor, status of the

elevators, designation of the attack stairwell, obtain building keys

(if necessary), and then proceed to their assignment.

Ventilation

In a high­rise, more than any other type of building, quickly

confining and extinguishing the fire are critical, as ventilation and

evacuation options are limited. Once the fire is extinguished, the toxic

products of combustion are no longer being produced, thereby

reducing the hazard level to firefighters and occupants and making

the operation more manageable overall.Another mode of ventilation

in a high­rise fire is positive pressurization. Positive pressure

ventilation (PPV) of a high­rise structure is achieved by placing fans

at the base of a stairwell and blowing air into the structure, as

illustrated in Figure 39.When appropriate openings or vents are used

in the structure, the airflow produced by the fan exhausts

contaminants to the outside. Fire departments use PPV as a means to

ventilate contaminated atmospheres after initial knockdown and

extinguishment of a fire.When configured properly, PPV fans can

meet or exceed previously established performance criteria for fixed

smoke control systems.Also, the stairs should be pressurized to

reduce smoke infiltration.It should also be noted that the pressurized

stairwell should be the stairwell of choice for occupant evacuation

(Kerber & Madrzykowski, 2007).

Figure 39: PPV fan ventilation

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During the experiments, the HVAC system was deemed

nonoperational. Once the fire was extinguished, PPV was used to

pressurize each stairwell. The roof hatch was opened to exhaust heat,

smoke and other combustion products to the outside. Placement of

the fans was handled by a firefighter from the first arriving truck.

8.3 Staging and Rehabilitation on Floor 8

Staging

In a high­rise structure fire, interior staging is set up in a safe

area two or more floors below the fire floor. Arriving crews not

directly assigned from the IC are typically dispatched to the

staging area to await a specific assignment. The reason for the

staging area is to provide a readily available reserve firefighting

force, as well as reserve equipment and supplies. Having these

resources available is a critical safety feature of high­rise response,

since the event may worsen very quickly or require more

resources than originally believed. Without resources near the fire

floor, it may take a considerable period of time to move people

and equipment from outside the building to the needed area.

The supervisorin charge of the staging area, or an aide, acts as the

accountability officerfor crews that are working outside of the staging

area (see Figure 40).The Staging Officer maintains a continuous log of

which companies are in Staging,which are in the rehabilitation area

(Rehab), and which are working on the fire floor orin other areas of

the structure.Tracking crew rotations can be a challenging,though

absolutely vital,task.

During the experiments, depending on crew size, the third or

fourth arriving truck company assumed the role of managing the

staging area. The duties of the staging area crew in the

experiments are listed below.

n Report directly to the IC

n Assign crews as directed by the IC

n Maintain a record of the companies in Staging and in Rehab

n Maintain a record of the companies working in other areas of

the building

n Request additional resources to maintain a reserve force (as

available)

n Maintain an adequate supply of air cylinders, search rope, water,

and other equipment, including EMS equipment as needed

Figure 40: Staging management

Rehabilitation

A rehabilitation area may also be set up at the staging area.

NFPA 1584 notes that a rehabilitation area should be established

whenever emergency operations pose the risk of pushing

personnel beyond a safe level of physical or mental endurance,

particularly when crews may be reassigned multiple tasks during

the same incident.

Specifically, NFPA 1584 provides a guideline that self­rehab with

hydration occur for at least 10 min following the depletion of one

30­minute SCBA cylinder or after 20 min of intense work without

wearing an SCBA. The standard further notes that firefighters

must enter a formal rehab area, drink appropriate fluids, be

medically evaluated, and rest for a minimum of 20 min following

depletion of two 30­minute SCBA cylinders, depletion of one

45­minute or 60­minute SCBA cylinder, or following 40 mins of

intense work without an SCBA.

The Rehab area in the high­rise field experiments was

established adjacent to the staging area on the 8th floor.

Firefighter/paramedics from the first arriving ambulance

established and managed the Rehab area. The area was used to

evaluate and assist personnel who had completed an assignment

in an IDLH environment. Within the Rehab area, firefighters

received a physical assessment, rest, hydration, evaluation, and

treatment (if necessary), continual monitoring of their physical

condition while in Rehab, transportation for additional

evaluation (if necessary), and reassignment to Staging, when

appropriate.

Time needed in Rehab is typically determined by the firefighter’s

level of physical conditioning, the atmospheric conditions, the

nature of the activities the firefighter was performing before

entering Rehab, and the time needed for adequate rehydration

and/or eating. While NFPA 1584 requires 10 min of rehab for

shorter work periods or 20 min for heavy work, as stated above,

the training protocol observed was conservatively required to be 15

min. Firefighters operating in the experiments were also required

to consume a minimum of one 12­oz (0.36 liter) bottle of water

before being sent to the staging area for possible reassignment.

8.4 Logistics of Material Support (Stairs/Elevators)

In high­rise operations, the logistical challenges of moving

firefighters, air cylinders, hoses, nozzles, ropes, forcible entry

tools, and EMS supplies increase with building height. If

additional firefighters and equipment are not moved into staging

and upper floors of the building early, early arriving crews will be

unable to sustain initial operations. The easiest way to transport

these resources is to use an elevator. If firefighters can safely use

the elevators, fireground logistics are dramatically improved.

However, if the elevator is not available or not safe to use, moving

firefighters and supplies up 10, 20, or more stories is an arduous

task. Having equipment available in the staging area in a timely

manner is a critical task, since later tasks may be delayed if the

equipment is not available when needed.

The high­rise field experiment study protocol addressed the use

of elevators, including circumstances in which it was unsafe for

firefighters to use them. The protocol included alternative

measures for getting needed equipment and firefighters to the fire

floor when elevators could not be safely used.

Stairwell support was the procedure used to move supplies to

the interior staging area when using elevators was not a safe

option. Firefighters assigned to stairwell support ascended and

distributed themselves evenly throughout the stairwell.

Equipment and supplies were then transported up the stairway

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using a firefighter relay system. Equipment was taken to the structure via the elevator (Figure 44) or stairwell (Figure 45),

interior staging area located two floors below the fire floor (8th according to the protocol governing the specific scenario. Once in

floor). Stairwell support was one of the first assignments given the lobby, the EMS personnel exited the building with the victim.

when the building was without elevator service due to the Time was recorded at the point that the victim was transferred to

location of the fire on an upper floor. the ambulance crew on the 8th floor and when the crew had

During the field experiments, both elevator and stairwell moved the victim to the exterior of the building.

support tasks were included in the scenarios in an effort to

measure the efficiency of each. A crew was assigned the task of

elevator or stairwell support (Figure 41 and Figure 42) depending

on the scenario being conducted. Elevator support was measured

in the scenarios in which elevators were deemed safe for use, and

stairwell support was measured in the scenarios in which the

elevators were deemed unsafe for use.

Figure 41: Elevator support Figure 42: Stairwell support

8.5 Ambulance Transport for Fire Victims

The number of ambulances (Emergency Medical Services (EMS

units)) needed to be available at a high­rise structure fire is

dependent on the number of people assumed to occupy the

structure and the number of firefighters operating at the incident.

There should be at least one ambulance available at all times

during a high­rise fire (IFSTA, 2011). Should one ambulance

transport a victim or firefighter from the scene, another

ambulance should be assigned by the IC to standby (Figure 43).

During the high­rise experiments, three ambulances/EMS Units

were used in the experiment. Though most ambulances were

staffed with two cross­trained firefighter/paramedics, all

ambulances were ALS units staffed with a minimum of one

firefighter/paramedic and one firefighter/EMT. The first arriving

ALS crew was assigned to operate the Rehab area. The second and

third arriving ambulance crews were sent to the staging area on

the 8th floor. As the victims were located during the search and

rescue operations, Ambulance 2 was assigned to transport the

victim who was being moved to the 8th floor from the fire floor

(10th floor) by the search and rescue team and Ambulance 3 was

assigned to transport the victim who was removed from the floor

above the fire (11th floor) and transferred to the 8th floor by the

search and rescue team.

Once assigned by the IC and staging manager, ambulance

personnel responded to meet firefighters bringing the victims to

the 8th floor stairwell landing. When a victim was received by the

firefighter/paramedics assigned to the ambulances, they

proceeded to carry the victim down to the lobby of the high­rise

Figure 43: Ambulance standby at high­rise structure fire

Figure 44: EMS personnel exiting with victim

rescued using a wheeled stretcher by elevators

Figure 45: EMS personnel carry victim

down stairs using a stair chair device

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8.6 Floor 9, Floor 12, and Floor 13 Search

and Rescue Operations

Search and Rescue Operations on floor 9 (the floor below the

fire) and upper floors (beyond Floor 11 — the floor above the

fire) were assigned to later arriving crews after higher priority

tasks in the more hazardous areas were underway. Along with

search ropes, forcible entry tools were carried by search crews to

force entry when necessary.

Search crews conducted a systematic search and collected blocks

or markers in the areas as they were searched. Collection of the

markers (blocks) was considered the equivalent of the typical

simple marking system used by most fire departments of placing a

chalk “X” on doors to rooms that had been searched and/or

indicating that a whole floor had been searched by marking

hallway doors or walls.

While the search crews were on air (any firefighter working

above the 8th floor landing was on air), the searches on these

floors revealed no smoke and no victims. Therefore, since there

was no smoke, the searches were walking searches.

After completing a thorough search of their assigned floor, crews

reported a search status to the IC and were then sent to the Rehab

area.

8.7 Floor 10 Suppression Operations

Fire suppression is a top priority during structural firefighting

operations. The ability to control the fire reduces the overall

hazard level for the occupants and firefighters, as well as reducing

property loss.

Equipment

Every suppression crew ascending to the fire floor carried

equipment, including four 50 ft (15 m) sections of 2 1⁄2 inch hose

(a total of 200 ft or 61 m), a gated wye valve28 to connect to the

building standpipe (riser) in the stairwell, and an extra air

cylinder.

Primary attack with 3­person crews

With 3­person crews, the initial attack line on the fire floor was

assigned to Engine 1 and Engine 2. Upon arrival on­scene, the

Engine 1 crew left the apparatus driver outside to connect the

hydrant to the engine pump (located on the street immediately

outside the building) and to connect the engine pump to the

building Siamese fitting in order to ensure adequate pressure for

sprinklers (if applicable) and for fire suppression operations

(standpipes). Throughout the incident the Engine 1 driver stayed

with the engine in order to ensure that adequate pressure was

continuously supplied to the standpipe and sprinkler systems. The

remaining two firefighters entered the lobby of the building to

begin an assessment of the situation. The Engine 1 officer

assumed incident command in the lobby. The third Engine 1

firefighter awaited the arrival of Engine 2 to ascend the stairs as a

composite, 4­person crew.

Primary attack with 4­person crews

With 4­person crews, the initial attack line on the fire floor was

assigned to Engine 1 and Engine 2. As with all crew sizes, Engine 1

left the apparatus driver outside to connect the water supply.

Throughout the incident, the Engine 1 driver stayed with the

engine in order to ensure that adequate pressure was continuously

supplied to the standpipe and sprinkler systems. The remaining

three firefighters entered the lobby of the building to begin an

assessment of the situation. As with 3­person crews, the Engine 1

officer assumed incident command in the lobby. The remaining

two Engine 1 firefighters awaited the arrival of Engine 2 to ascend

the stairs (thus ascending as a 6­person crew, consisting of two

from E1 and four from E2).

Primary attack with 5­ and 6­person crews

With 5­person and 6­person crews, the initial attack line on the

fire floor was assigned entirely to Engine 1. As with all crew sizes,

the apparatus driver stayed outside to connect the water supply to

the building. The remaining 4 (or 5) firefighters entered the lobby

of the building to begin an assessment of the situation. Unlike

3­person or 4­person crews, Engine 1 left a firefighter to assume

Lobby Control, while the officer stayed with the Engine 1 crew to

ascend to the fire floor. The remaining 3 (or 4) Engine 1

firefighters then immediately ascended the stairs (rather than

waiting for Engine 2) to begin fire attack and suppression.

Fire Floor Suppression Operations

Upon arrival on the landing for Floor 9, the initial suppression

company arrived at the standpipe, removed the pressure reducer

and connected a pressure gauge. A firefighter then connected the

gated wye valve to the building standpipe, connected a section of

2 1⁄2 inch hose to the wye, and flaked out the line in the stairwell

(following the stair from the 9th floor landing, past the 10th floor

to the 11th floor landing, and back down to the 10th floor). Under

real firefighting conditions, the hose line would be charged (filled

with water) prior to making entry onto the 10th floor; since the

experiments were not flowing water (in order to protect the

building from the effects of water), the suppression team used a

sand­filled 2 1⁄2 inch hose line located immediately adjacent to the

stairwell door in the core of the building (see Figure 46). The

attack line was pulled from the stairwell through the elevator

lobby and entered the fire compartment through a door in the

opposite corner of the core. Entering the fire floor was always

coordinated with Truck 1 (which did not commence search and

rescue until the suppression team was ready to flow water). Upon

entering the fire compartment, the initial attack line proceeded to

the left and began suppression operations (as shown with the

word “Start” in Figure 46). Suppression involved simply moving

the nozzle of the hose line through the fire area to the seat of the

fire (shown with the word “Stop” in Figure 46). Even after the fire

was deemed “out”, the hose lines were staffed for the duration of

the experiment in order to protect the fire floor from a “rekindle”

scenario, while search crews were operating in the environment.

Each crew assigned to the attack or second line on the fire floor

was allowed to remain on air for 15 min, as described in section 6.7,

and then called for relief.

Suppression Technique

Extending the hose lines on the fire floor (10th Floor) required

crews to pull more than 200 ft (51 m) of 2 1⁄2 inch hose,

maneuvering through five right­angle corners. Each corner

represented a significant friction point for hose line operations;

thus, a crew member was typically left at each corner in order to

pull the line through the corner and ease the effort of the crew

members at the nozzle end of the line. This hose handling

technique was discussed each day with engine crews in order to

help ensure consistency during the tests.

28. Gated wye valves divide one line into two. The valve is often constructed of aluminum and plastic with hard coated threads and has a female inlet with two male outlets.

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Figure 46: Pathway of hose lines from core through the fire area. The double dash lines represent the need for

both hose lines to be present

Second Attack Line

For crew sizes of 3 and 4 persons, Engine 3 was assigned

responsibility for deploying the second line on the fire floor. It is

important to note that the second line was engaged in attack. The

fire on Floor 10 was so large (more than 8 MW, involving several

thousand square feet of fire involvement) that a single 2 1⁄2 inch

line would not have been sufficient to extinguish the fire. For 5­

and 6­person crews, Engine 2 was assigned responsibility for the

second line on Floor 10. Similar to the initial attack line, the

second line crew connected a 2 1⁄2 inch hose to the gated wye valve

on the stairwell landing of Floor 9 and flaked the hose up and into

Floor 10. The second line on Floor 10 was also a sand­filled 2 1⁄2

inch hose located immediately outside the stairwell door to the

building core. The second line followed the same path to the seat

of the fire as did the primary attack line. The fire was determined

to be extinguished (Fire Out time) when the nozzle for the second

line reached the seat of the fire as denoted by the word “Stop” in

Figure 46. As with the primary attack line, the second line was

subsequently staffed for the duration of the fire.

8.8 Floor 10 Search and Rescue Operations

Two significant efforts occurred in parallel on the fire floor: fire

suppression and search and rescue. Fire suppression is typically

the primary task of engine companies, while search and rescue

operations are typically the responsibility of truck companies. The

primary purpose of the search and rescue operation was to locate

and extricate building occupants who may be trapped or

otherwise require evacuation assistance. Consistent with

prevailing common practices in the fire service, the suppression

crews and rescue crews made entry to the fire compartment

together. Having a hose line actively knocking down the fire is

particularly important for the search and rescue companies

because it reduces risks, including the likelihood of becoming

trapped and/or overwhelmed by a growing fire.

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Figure 47: Schematic of the fire floor

Overview of Fire Floor Search Patterns

As shown in Figure 47, the fire floor (Floor 10) is an open­floor

plan office layout. The core area contains two stairwells, four

elevators, and a perimeter hallway with floor to ceiling walls

separating the office space from the core area. This arrangement

provides an area of protection from smoke and heat for

evacuating occupants, as well as responding firefighters.

Firefighter access to the fire floor was always through the attack

stairwell. The crews then made entry to the floor from the

doorway shown in Figure 47, roughly opposite the location of the

attack stairwell. By maintaining a consistent entry point, Division

10 (Fire Floor Supervisor), could maintain crew accountability

and know which resources were operating in the fire environment

at any point in time. The arrangement of cubicles on the fire floor

roughly formed two hallways that were continuous loops

(referred to as the inner and outer loops for the purposes of these

experiments).

Search and Rescue Technique

Search and rescue operations on the fire floor were always

conducted under low visibility and simulated IDLH conditions.

Thus, searches were conducted while crawling on hands and

knees. The exception to crawling was when a crew used a search

rope placed by a prior crew. Relief crews were allowed to hold a

previously placed search line in their hand while they proceeded

through a previously searched area until they found where the

crew before them had stopped. Once the relief crew reached the

end point of the prior crews’ search area, as indicated by either a

search bag or a search tool, they once again began to crawl.

As each crew depleted their air supply or search rope, they called

for relief. Upon calling for relief, the search crew walked (again

holding the search rope as a guide) back to the entry door and

communicated with the Division 10 officer, and then reported to

Rehab.

All searches used a right­hand search technique for

consistency.29 The crew followed the inner (or outer) hallway,

searching cubicles encountered along the way. As a crew

encountered a cubicle, one firefighter stayed ‘on the line’ while

another member of the crew searched the cubicle. Each firefighter

was required to stay in visual, voice or rope contact with at least

one other firefighter. Losing a search partner or the search rope is

a dangerous situation for the search and rescue crew since it can

lead to disorientation and difficulty in finding an exit from the

floor. Once each cubicle was cleared, the crew proceeded to the

next cubicle, clearing the hallway as they proceeded. Crews with

three members could leapfrog cubicles, searching two

simultaneously, while the officer or another firefighter continued

to deploy the search line and maintain crew accountability.

While searching a cubicle, the firefighters used one of several

common techniques. As each technique was roughly the same in

29.A right­hand search is one in which every compartment is searched starting to the right until the searcher has completed a path,returning to the starting point.

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terms of time to completion and energy expended, the study team

did not prescribe a particular technique. One common technique

was for the firefighter to crawl the perimeter of the cubicle, using

the right­hand search pattern to search for a victim. A second

technique was for the firefighter to assume a position in the center

of the cubicle and then use a pike pole, axe, or Halligan tool to

sweep the entire cubicle perimeter for a victim. A third technique

was for the firefighter to assume a position in the center of the

cubicle and then use their leg to sweep the perimeter of the

cubicle in order to find a victim. These three techniques all

implemented a tactile strategy for locating victims, which is

critical under low visibility conditions. The primary tactile

strategy was supplemented by a secondary strategy of

flashlights/headlights and visual searches in the limited

circumstances when the smoke conditions allowed for local

visibility.

Search Lines (Tag lines)

Search and rescue companies utilize search lines (rope) for three

reasons. First, the search line provides an assured path back to the

point­of­entry on the fire floor. Second, the search line provides

relief crews with a physical indicator of which portions of the

floor have been previously searched. Third, the length of the

search line (typically 200 ft (61 m)), when combined with

effective air management, helps search crews consider when the

crew has performed their task and should call for a relief crew.

Typically, search and rescue crews deploy search lines as they

proceed through the structure. Initial shake­down tests revealed a

fair degree of variation in search line or rope deployment from

one crew to another. Therefore, in order to improve experimental

reproducibility, search lines were pre­positioned on the fire floor

(see discussion of deployment patterns below).

Search and Rescue Relief

In the high­rise experiments, search and rescue companies

completed their assigned task and called for a relief crew under

one of three conditions:

n A member of the company had a low­air indicator on their

bottle.

n The handheld timer30 activated, indicating that the company

was nearly out of air.

n The company deployed and searched 200 ft (61 m) of search

line.

The company officer radioed the Battalion Chief in charge of

fire floor operations (Division 10) to request relief. Division 10

acknowledged the request and then communicated with the

Incident Commander in order to have a relief crew sent to the fire

floor from Staging. Upon calling for relief, the company would

either leave the rope bag or leave a search tool (such as an axe,

Halligan tool, or pike pole) in order to mark the end of their

search, so that the relief company could locate the transition point

between searched and unsearched floor space. The company then

followed the search line back to the point of entry for the floor.

Upon reaching the entry door to the fire compartment, the

company officer conducted a face­to­face discussion with either

Division 10 or with the officer from the relief crew (or both). The

purpose of the discussion was to summarize what activities were

accomplished, provide a sense of direction and/or distance to the

point where activities terminated, and any other task­relevant

information, such as the location of any special hazards. Once the

face­to­face discussion was completed, the company exiting the

fire floor reported to the designated rehabilitation floor in order

to obtain fluids, rest, and be physically assessed for fitness to

return to operations.

Search and Rescue Search Strategy

Crew size has a dramatic impact on the manner of crew

deployment for search and rescue operations. This is due to the

ability of larger search and rescue companies to split into multiple

crews and search the floor area in parallel, rather than in series.

Since all fireground operations in IDLH environments must be

conducted with at least two persons for safety and accountability,

a search and rescue crew can form two teams only when there are

at least four members. Five­person companies can form a team of

two firefighters and a team of three firefighters. While 6­person

crews can typically form three 2­person crews, during the

experiments, the nature of the search on the fire floor dictated the

formation of two teams of 3 firefighters. One crew retained the

base company moniker (e.g., Truck 6), while the second crew

adopted an X­ray suffix (e.g., Truck 6 X­Ray) in order to

distinguish the crews, particularly for radio traffic purposes.

A complicating reality for the first arriving truck crew was the

assignment of one member to establish Lobby Control and

establish positive pressure ventilation in the two stairwells serving

the building. As a consequence, the first arriving crew had one less

member than subsequent arriving search and rescue teams. This

assignment had a significant impact on the operational

effectiveness of some crew configurations, as described below.

30.A timer with audio (beeping), visual(flashing lights), and tactile (vibrating) alarm indicators was provided to each company officer as they went ‘on air’.This typically occurred

while leaving the 8th floor(staging) and going into an IDLH environment. Each timer was set to alarm after 13 min, allowing 2 min forthe relief crew to arrive.

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Figure 48: Fire floor search by 3­person crew

Three­Person Search Crews

The first­arriving 3­person crew (Truck 1) left one member in

the lobby for PPV in the stairwells (as described above). Thus,

Truck 1 became a two­person crew for the remainder of the

experiment. After completing the Check for Fire Extension task,

Truck 1 commenced a right­hand search on the inner loop of the

fire floor, at the location in Figure 48 marked by Symbol 1 (the

number 1 in a green circle). In most circumstances, Truck 1

searched for 200 ft (61 m) and called for relief upon reaching the

end of the search rope (marked by Symbol 2). No crew was

allowed by convention to search more than 200 ft (61 m). The

relief crew operating with 3 firefighters followed the inside loop

search rope, starting the search once the search bag (or search

tool) left by Truck 1 at Symbol 2 was located. As the second search

crew completed the inside loop search, the search was continued

by crossing to the outside loop and commencing to the right. The

second search crew typically completed their search when they

ran out of rope at Symbol 3 in Figure 48. After calling for relief

and leaving an indicator for the next search crew, the second crew

followed the search line back to the entry door, roughly 60 ft (20

m) from their stop point, and communicated with Division 10

and/or the relief crew. Division 10 was located at the symbol with

“D10” within a white circle. The relief company proceeded to the

end of the search rope located along the outer loop at Symbol 3

and resumed the search. The third crew typically encountered the

fire floor victim, represented in Figure 48 and subsequent figures

by the word “Victim” in a yellow star. Procedures for victim

rescue have been described previously in this report. As the victim

rescue required the effort of all 3 crew members, a fourth search

company was called to the fire floor when the victim was located.

With only three full alarms available for this incident response,

the only search crew available was one that had completed a prior

task, had been processed through Rehab, and had been declared

fit for return to operations by the ALS medic crew. The final

search crew on the fire floor followed the outer loop search line

from the entry door to the location where the victim was found

(Symbol 4) and completed the fire floor search. The location of

the search completion is shown by the Stop symbol in Figure 48.

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Figure 49: Fire floor search by 4­person crew

Four­person Search Crews

The first­arriving 4­person crew (Truck 1) left one member in

the lobby to handle PPV for the stairwells (as described

previously). Thus, Truck 1 operated as a 3­person crew for the

remainder of the experiment. After completing the Check for Fire

Extension task, Truck 1 commenced a right­hand search on the

inner loop at Symbol 1 in Figure 49. In most circumstances, Truck

1 searched for 200 ft (61 m) and then called for relief upon

reaching the end of the search rope at Symbol 2. The relief crew,

operating with four personnel, split into two search teams (one

team on the inside loop and one team on the outside loop). The

relief crew on the inside loop followed the search rope previously

searched by Truck 1 until they located the search bag (or search

tool) left by Truck 1 at Symbol 2. The relief crew then continued

searching until the inner loop search was complete. Once

complete, the crew on the inner loop waited briefly to reassemble

with the X­Ray team. The relief X­Ray crew commenced the outer

loop search at Symbol 2X, typically finding the incapacitated

victim at the star. Upon locating the victim, the X­Ray crew

informed Division 10 that a victim had been located and that an

ambulance team was needed to meet them in the stairwell. In

addition, as an ambulance was requested, relief was also requested

so that another crew could be sent to complete the search on the

fire floor. The second crew members all met in the stairwell to

maintain full crew accountability. The crew carried the victim to

meet the EMS crew on the 8th floor and then proceeded to Rehab.

A third crew then relieved the second and completed the search of

the outer loop on the fire floor from Symbol 3 as a 4­person crew.

The location of the search completion is shown by a stop sign in

Figure 49.

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Figure 50: Fire floor search by 5­ or 6­person crew

Five­person Search Crews

The first­arriving 5­person crew (Truck 1) left one member in

the lobby to handle PPV in the stairwells (as described above).

Thus, Truck 1 operated as a 4­person crew for the remainder of

the experiment. Upon arrival on the fire floor, Truck 1

immediately split into Truck 1 and Truck 1 X­Ray crews. Truck 1

completed the Check for Fire Extension task, and then started a

right­hand search on the inner loop, beginning at Symbol 1 in

Figure 50. Truck 1 typically searched for 200 ft (61 m) and called

for relief upon reaching the end of the search rope at Symbol 2.

Meanwhile, Truck 1 X­Ray commenced the outer loop search at

Symbol 1X, typically finding the incapacitated victim at the star.

Upon locating the victim, Truck 1 X­Ray informed Division 10

that a victim had been located and that an ambulance crew was

needed to meet them in the stairwell. In addition, relief was

requested in order to complete the search on the fire floor. Truck 1

met the X­Ray team in the stairwell to maintain full crew

accountability. The crew delivered the victim to the EMS crew on

the 8th floor landing and then proceeded to Rehab. The relief

crew, operating with all 5 personnel, split into two search teams

(one team with 2 persons on the inside loop and the other team

(X­Ray) with 3 persons on the outside loop). The crew on the

inside loop followed the search rope until they located the search

bag (or search tool) left by the previous crew then continued

searching until the inner loop search was complete. Upon

completion, the crew waited briefly to reassemble with the X­Ray

team. The X­Ray crew typically completed the search of the outer

loop on the fire floor.

Six­person Search Crews

The first­arriving 6­person crew (Truck 1) left one member in

the lobby to handle PPV in the stairwells (as described

previously). Thus, Truck 1 operated as a 5­person crew for the

remainder of the experiment. Upon arrival on the fire floor, Truck

1 immediately split into Truck 1 and Truck 1 X­Ray crews. Truck 1

completed the Check for Fire Extension task, and then started a

right­hand search on the inner loop, beginning at Symbol 1 in

Figure 50. Truck 1 typically searched for 200 ft (61 m) and called

for relief upon reaching the end of the search rope at Symbol 2.

Meanwhile, Truck 1 X­Ray commenced the outer loop search at

Symbol 1X, typically finding the incapacitated victim at the star.

Upon locating the victim, Truck 1 X­Ray informed Division 10

that a victim had been located and that an ambulance crew was

needed to meet them in the stairwell. In addition, relief was

requested in order to complete the search on the fire floor. Truck 1

met the X­Ray team in the stairwell to maintain full crew

accountability. The crew delivered the victim to the EMS crew on

the 8th floor landing and then proceeded to Rehab. The relief

crew, operating with all 6 personnel, split into two search teams

with 3 persons each. The crew on the inside loop followed the

search rope until they located the search bag (or search tool) left

by the previous crew at Symbol 2, then continued searching until

the inner loop search was complete. Upon completion, the crew

waited briefly to reassemble with the X­Ray team. The X­Ray crew

typically completed the search of the outer loop on the fire floor

from Symbol 2X.

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Victim Rescue

The victim on the fire floor was rescued using a proper rescue

technique requiring two firefighters, one of whom used webbing to

lift the victim under the shoulders, and the other who lifted the

victim’s legs. Once properly packaged, the firefighters proceeded to

the evacuation stairwell and moved down to Floor 8 where they were

met by an EMS crew.At that time, emergency care was transferred to

the EMS crew and the two firefighters proceeded to Rehab.

Management of Fire Floor Operations

The second arriving Battalion Chief (BC2) was assigned the

responsibility for managing the fire floor operations. Upon

arriving on the fire floor, BC2 became Division 10. Division 10

also had an aide to assist in managing and recording the flow of

personnel and information. Due to travel times, BC2 and the aide

arrived on the fire floor and established Division 10 shortly after

the fire floor operations were initiated by Engine 1, Truck 1, and

Engine 2. Upon establishing Division 10, all fire floor

communications were directed through Division 10 in order to

limit the radio traffic to the Incident Commander. The location of

Division 10 is shown by the symbol “D10” in a white circle in

Figure 48 through Figure 50.

A key task for Division 10 was crew accountability. With the

exception of the early arriving crews, all companies performed a

face­to­face check­in with Division 10 before entering the fire

compartment and all units performed a face­to­face check­out

with Division 10 as they left the fire compartment to ensure

accountability for all firefighters.

8.9 Floor 11 Suppression Operations

In addition to extinguishing the fire, two of the primary

objectives of high­rise fireground operations are to conduct a

primary search on the fire floor and the floors above and to check

for fire extension on the floor above the fire.

The floor above the fire is considered a high hazard environment

due to the threat of rapid fire and smoke spread vertically.

Occupants on the fire floor and above are normally in the greatest

danger due to the probability of fire extension. In many buildings

fire­resistive construction should contain the body of a fire to the

fire floor; however, there is a need to deploy at least one

precautionary hose line on the floor above the fire.

During the high­rise experiments, a 2 1⁄2 inch hose line was

deployed to the 11th floor (immediately above the fire) as a

precaution. Additionally, the suppression crew also pulled ceiling

tiles to check for fire extension in the ceiling. Although crews

responding to the 11th floor encountered heavy smoke, there was

no fire extension. To assure the safety of search crews, fire

suppression crews stood by in the area above the location of the

fire for the duration of the search on the 11th floor.

8.10 Floor 11 Search and Rescue Operations

Overview of Floor 11 Search Patterns

The 11th floor was a completely different environment from the

fire floor. Floor 11 was highly compartmentalized with four

distinct, fully segregated areas. Figure 51 shows a bird's eye view

of floor 11. As shown, there are a few areas of open floor space

with many offices dispersed throughout.

Figure 51: Schematic of floor 11 59
     

                     

                        

                     

                           

                         

                      

                     

                       

                     

     

                     

                 

                 

                     

               

   

                 

                   

               

               

                         

                   

                           

                             

               

                 

                         

               

                   

                     

               

                 

                   

               

                       

                 

       

                       

                       

     

             

                 

                     

                     

                           

                 

                           

                         

                   

                       

                       

                       

               

                   

                   

               

                     

                       

                   

                     

                       

                       

                    

                   

Search and Rescue Technique

The search and rescue operations on the floor above the firewere

different from those on the fire floor. All crews entered the floorthough

the door directly east of the evacuation stairwell and depending on crew

size, began either a right hand search or both a left and right hand search.

Aswith floor 10, crews could only split to search if they maintained two

personsin each team. While the first and lastsectionssearchedwere

near zero visibility,the remainder of the floor had good visibility. Fire

crews used search lines(ropes) and crawled in areas of lowvisibility (first

and lastsections) andwalked in areas of good visibility (middle section).

Search and Rescue Relief

As on floor 10, when crews needed relief they radioed the Division

Commander. On Floor 11, Division 11 was established by BC3.

The need for crew relief was dictated by three conditions:

n A member of the company had a low­air indicator on their bottle.

n The handheld timer activated, indicating that the company was

out of air.

n The company deployed 200 ft (61 m) of search line.

The company officer radioed the Battalion Chief in charge of fire

floor operations (Division 11) to request relief. Division 11

acknowledged the request and then communicated with the Incident

Commander in order to have a relief crew sent to the floor above the

fire from staging. Upon calling for relief, the company would either

leave the rope bag or leave a search tool (such as an axe, Halligan tool,

or pike pole) in order to mark the end of their search so that the relief

company could locate the transition point between searched and

unsearched floor space. The company then followed the search line

back to the point of entry for the floor. Upon reaching the entry door

to the interior compartment, the company officer conducted a

face­to­face discussion with either Division 11 or with the officer from

the relief crew (or both). The purpose of the discussion was to

summarize what activities were accomplished, provide a sense of

direction and/or distance to the point where activities terminated, and

any other task­relevant information,such as the location of any special

hazards. Once the face­to­face discussion was completed, the company

exiting the floor reported to Rehab in order to obtain fluids,rest, and

be physically assessed for fitness to return to operations.

Search and Rescue Crew Deployment

In all scenarios, an engine and a truck were assigned to the floor

above the fire upon their arrival. All relief crews to Floor 11 were

sent from Staging.

Figure 52: Floor 11 search by 3­person crew

Three­person crews

Since 3­person crews must maintain crew integrity at all times

(cannot split into two teams),the first crew started with a right­hand

search of the first compartment.The start of the first truck crew’s

search is shown in Figure 52 as the number 1 in a green circle, or

Symbol 1.Aftersearching this first compartment,(ending at the

number 1 in a red Stop sign)the initial truck crew was out of rope,

and often out of ‘on air’ time.At this point,the first crew would

communicate the extent of theirsearch to Division 11 and request

relief.The next crew on the floor began theirsearch at the location

shown by Symbol 2.As indicated by the line style,this second crew

began theirsearch by crawling, but as they entered the inner core of

the building beyond the first compartment the visibility conditions

improved, allowing them to walk the next portion of theirsearch.

After covering the west end of the building,the second crew

encountered another compartment of heavy smoke, causing them to

revert back to crawling.Very shortly after entering this area, at Symbol

Stop 2,the second crew ran out of search rope,requested relief and

proceeded to Rehab.The final crew continued where the second left

off at Symbol 3 and finished theirsearch by finding the incapacitated

victim (represented in Figure 52 as the word “Victim” in a yellow star).

The search crew then carried the victim to the 8th floor,where they

were met by the EMS crew. Meanwhile, Division 11 requested another

search crew from staging to complete the search on Floor 11.

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Figure 53: Floor 11 search by 4­person crew

Four­person crews

Since 4­person crews are able to split into two crews and still

maintain a minimum crew size of two, the initial truck crew

entering Floor 11 could begin both right­hand and left­hand

searches, denoted by Symbols 1 and 1X in Figure 53. Due to the

width of the first compartment, the initial crew was unable to

span the entire compartment and was required to trace back

along their search rope and cover the center of the floor. After

completing the search of the first compartment, the first truck

company ran out of rope and depleted their ‘on air’ time at

Symbols Stop 1/1X and needed to be replaced. Working through

Division 11, located at the symbol with “D11” within a white

circle, the crew called for relief and then proceeded to Rehab. The

next crew on the floor picked up at the start point shown as the

isolated Symbol 2 in Figure 53. As with the second crew for the

3­person crews, the initial section of the search had limited

visibility, but after the first compartment visibility improved.

When the second crew reached the last compartment, the

visibility again decreased, forcing a crawling search. At this point,

the crew split into two crews of two. One crew began a right hand

search at Symbol 2 while the second crew (X­Ray) began a left

hand search at the nearby Symbol 2X. During this portion of the

search, the X­Ray crew encountered the incapacitated victim at

the star, forcing both firefighters to leave the floor with the victim.

The remaining two members of the full crew continued to search

until they ran out of rope or ‘on air’ time at Symbol Stop 2. When

relief was called, a final crew was sent in to finish searching the

remaining area from Symbol 3 to Symbol Stop 3.

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Figure 54: Floor 11 search by 5­person crew

Figure 55: Floor 11 search by 6­person crew

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Five­ and six­person crews

As shown in Figure 54 and Figure 55, the initial crew for

5­person and 6­person crews behaved the same. The initial crew

made entry onto the floor and began a right­ and left­hand search

of the first compartment, starting at Symbol 1 and Symbol 1X

respectively. Unlike the 4­person crews, the 5­person and

6­person crews were able to span the entire width of the

compartment, which allowed them to progress past the first

compartment without the need for relief. This first crew of 5 or 6

firefighters was able to search beyond the point where the first

crews of 3 and 4 persons had to stop. The larger crews continued

forward to search the floor until they ran out of search rope or ‘on

air’ time at Symbol Stop 1. The first truck crew made it as far as

the door into the last compartment. From this point the 5­person

and 6­person crews differ, so each will be individually discussed.

The final 5­person crew

Upon entry to the last compartment at Symbols 2/2X in Figure

54, the five­person crew split into two crews. The X­Ray crew had

2 firefighters, leaving 3 for the other crew. The X­Ray crew found

the victim shortly after entry. The X­Ray crew then packaged the

victim, transported the victim down to meet the EMS crew on the

8th floor and then went to Rehab. The remaining members of the

second crew finished the search of the floor.

The final 6­person crew

As with the 5­person crew, the second truck crew made entry

into the last compartment at the location marked by Symbols

2/2X in Figure 55. The major difference between the 5­person and

6­person crews at this point is that with 6 members, the X­Ray

crew could transport the victim down to the 8th floor to meet

EMS while leaving 4 firefighters to complete the search. From here

the remaining crew split again into two crews of two and finished

the remaining search.

Victim Rescue

The victim on the floor above the fire was rescued using the

same method as for the victim on the fire floor. Proper rescue

technique required two firefighters, one using webbing to lift the

victim under the shoulders, and the second firefighter to lift the

victim’s legs. Once properly packaged, the firefighters proceeded

to the evacuation stairwell and moved down to Floor 8 where they

were met by an EMS crew. At this time, emergency care was

transferred to the EMS crew and the two firefighters proceeded to

Rehab.

Management of Floor 11 Operations

As noted previously, BC3, upon arrival to the scene, was assigned

to Division 11. Within this role, Division 11 was responsible for all

operations and communications on Floor 11. When Division 11

made entry to the 11th floor, crews were already manning a hose

line above the fire, and a crew was already searching the floor.

Division 11 established the area just outside of the evacuation

stairwell as his command area, marked by the symbol “D11” in a

white circle in Figure 52 through Figure 55, since all crews must

move through this stairwell to access the floor. This location

allowed face­to­face exchange with crews entering and exiting the

area. The face­to­face communications with arriving and

departing crews also allowed Division 11 to know the progress

being made on the floor. While there was heavy smoke, there was

no fire extension onto the floor. However, the hose line was always

staffed while a search crew was operating on the floor.

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9. Analysis of Experimental Results
 

This section describes the analytic approaches used to

address the research objectives of the study. First the

statistical methods used to analyze the high­rise fireground

time­to­task observations are presented. Then the time­to­task

data and the fire modeling data are combined to assess crew

performance in relation to tenability within the structure.

9.1 Time­to­Task Analysis

Time­to­task data were compiled into an analytic database. The

data were reviewed for logical consistency, outliers, and missing

entries. A small amount of editing was performed to clean up the

data. Because all experiments were conducted in triplicate,

missing data were readily apparent and were reviewed against the

recorded radio tape information. Missing data were replaced by

times calculated from the radio recordings. Where radio

documentation proved inadequate, missing data were entered

using the mean task time from the corresponding two observed

field replicates. The amount of data requiring such imputation

was minimal (less than 0.05 %).

9.2 Data Queries

The methods used to analyze the time­to­task data were driven

by the principal goal of assessing the effects of crew size on task

timing measures (i.e., start, duration, end) for critical steps in the

high­rise response, while controlling for ascent mode and alarm

size. This research goal motivated the development of five specific

research questions (see Figure 56) that in turn motivated specific

statistical models and analyses for generating inference. The

critical tasks are presented in Table 5.

Time­to­Task Research Questions

1) How do crew si e, ascent mode (stairs vs. elevator)

and si e of full alarm assignment (i.e., alarm si e

low versus high) affect overall (i.e., start to

completion) response timing?

a. How do variations in crew si	 e affect overall
 

response timing?
 

b. How much does ascent mode affect overall
 

timing?
 

c. How much does si	 e of full alarm assignment

affect overall response timing?

d. How do overall response times vary by

combinations of crew si e, ascent, and alarm

si e?

Figure 56: Time­to­Task Research Questions

! Critical Task:

1 Advance Attack Line

2 Advance Second Line

3 Fire Out

4 Establish Stairwell/Elevator Support

5 Search and Rescue 10th Floor

6 Victim #1 Found

7 Victim #1 Rescue

8 Victim #1 Descent

9 Search and Rescue 11th Floor

10 Victim #2 Found

11 Victim #2 Rescue

12 Victim #2 Descent

13 Advance Line Above Fire

14 All Tasks Complete (timer sheet)

Table 5: Critical tasks considered in analysis

9.3 Statistical Methods — Time to Task

The analysis of the time­to­task data involved a sequence of

multiple linear regressions using Ordinary Least Squares to

generate and test the effects of crew size, alarm size and ascent

mode on timings. The regressions were of the form:

Where yi represents the ith dependent/outcome variable, xik

denotes the factors such as vertical ascent mode and crew size

whose effects on yi are being tested, and βk is the set of regression

coefficients that minimizes the set of errors εi. The three potential

dependent (outcome) variables for each critical task listed in

Table 5 were:

n Begin time (i.e., the time at which a task commenced),

n Duration time (i.e., the time it took to complete the task), and

n End time (i.e., the time of task completion).

Three sets of independent variables were included: crew size (3,

4, 5, 6); ascent mode (elevator, stairs) and alarm size (low, high).

Dummy variables were used for these controlling factors in the

regressions. Regressions were performed for each task­outcome

combination, so that the impacts of crew, alarm and ascent could

be examined by task individually and in combination (according

to the research question being addressed). These regressions

permitted the development of specific contrasts (e.g., to look at

64
the effects of incremental changes in crew size) that were used to when incrementing from a smaller crew size to a larger crew size,

address the research questions posed in Figure 56.  e.g., 3 to 4, 4 to 5, or 3 to 5.

Figure 58 presents the average completion times by ascent mode

9.4 Regression Analyses

Regression results

Appendices B1 to B3 present the regression results used to

generate the findings in this chapter. Regression models were

developed for each relevant critical task and outcome

combination. Additional regressions were performed to explore

the effects of specific combinations of crew and alarm size as well

as combinations of ascent mode and alarm size. The regression

for each crew size. The patterns across crew size are similar by

mode. The use of elevators reduced overall completion time

relative to ascent by stairs. For any given crew size, the reduction

in the time to complete all tasks attributed to ascent mode was

roughly in the 3 min to 5 min range in favor of elevators.

Overall Time To Task Completion

Crew Size / Ascent Mode

00:10:1 00 :10: 00

aT sk Time From Initiation to Completion

results include the coefficient values, their standard errors and

their corresponding levels of significance. 

Rather than detailing each of the lengthy lists of coefficients

found to be significant, specific summaries of these results were

compiled in order to address the primary research questions

presented in this chapter. Appendices C1 to C4 provide a detailed

summary of regression findings, and Appendix C5 presents a

tabular summary of all statistically significant findings.

Overview of Time­to­Task

1:00:00

0:50:00

0:40:00

0:30:00

0:20:00

0:10:00

0:00:00 As a segue to the statistical regression analyses, an overview of 3- 4- 5- 6- 3- 4- 5- 6-

Person Person Person Person Person Person Person Person the time­to­task results for the different crew sizes used in these Stairs Stairs Stairs Stairs Elevator Elevator Elevator Elevator 

experiments is presented, along with an examination of how each End Time 5204:1: 5204: 52:0:24 2544:0: 2544: 41:0:07 00:1:14 4548:0: 4548: 38:0:47 0438:0: 0438:

Duration 1:04:52 0:52:24 0:44:25 0:41:07 1:00:14 0:48:45 0:38:47 0:38:04 result varied when introducing the two other factors that were Start Time 0:00:00 0:00:00 0:00:00 0:00:00 0:00:00 0:00:00 0:00:00 0:00:00

variables in the study — vertical ascent method and alarm size.

Figure 57 presents the overall average times to completion for each Figure 58: Time to complete by crew size and ascent mode

crew size tested in the field experiments. As one would expect, the

time to completion decreases as crew size increases. Three­person Figure 59 presents the average completion times by crew size and

crews took an average of about an hour to complete their fire alarm size (low vs. high). Again, the patterns by alarm size are

response, while crews of 6 firefighters required a mean time of just similar across crew sizes. For three of the four crew sizes (4, 5, and

under 40 min for completion. The performance of crews with 4 and 6) average completion times are slightly shorter for high response

5 firefighters were between these two values, with crew size 5 taking compared to low response, with differences ranging from just over

about 2 min longer than crew size 6, and crew size 4 taking about 9 a half minute to about 3 min. While these results suggest little

min longer than crew size 5 but 12 min less time than crew size 3. impact of alarm size on overall time to completion for a given

The findings from the crew size analysis suggest that size does matter crew size, it does leave open the possibility that specific

when it comes to number of firefighters assigned to crews. Even the combinations of crew size and alarm size may outperform others

increment of a single firefighter can have a positive impact on the — e.g., 4/high versus 5/low. This possibility will be explored later

start, duration and completion of varied critical tasks. Incrementing in the regression analyses.

crew size by two is also beneficial. The most sizeable gains were seen

Overall Time To Task Completion

Crew Size 

Overall Time To Task Completion

Crew Size / Alarm Size

aT sk Time From Initiation to Completion

aT sk Time From Initiation to Completion

:10:1 00 00:10:1 00 :10: 00

1:00:00

0:50:00

0:40:00

0:30:00

0:20:00

0:10:00

1:00:00

0:50:00

0:40:00

0:30:00

0:20:00

0:10:00

0:00:00 3- 4- 5- 6- 3- 4- 5- 6-

0:00:00 Person Person Person Person Person Person Person Person 3-Perso n 4-Person 5-Person 6-Person Low Low Low Low H igh High High High

nd TE ime 02:1: 33 0: 50:34 0: 3641: 3539:0: 3539: End Ti me 0402:1: 0402: 0:50:53 3442:0: 3442: 0:41:03 1: 03:02 1650:0: 1650: 0:40:38 0838:0: 0838:

Durati on 1:02: 33 0: 50:34 0:41:36 0:39:35 Durati on 1:02:04 0:50:53 0:42:34 0:41:03 1: 03:02 0:50:16 0:40:38 0:38:08 

Start Time 0:00:00 0:00:00 0:00:00 0:00:00 Start Time 0:00:00 0:00:00 0:00:00 0:00:00 0:00:00 0:00:00 0:00:00 0:00:00 

Figure 57: Time to complete all tasks by crew size Figure 59: Time to complete all tasks by crew size and alarm size

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Figure 60: Start and end timing of critical tasks by crew size

Critical Tasks

In this section the subset of tasks deemed ‘critical’ in the

firefighter high­rise response is examined. Different timing

outcomes (begin, duration, end) are important to consider for the

subset of tasks, listed in Table 5. An overview of critical task

timings is presented by crew size in Figure 60, which shows the

overall average start and completion times for each crew size and

critical task, including overall completion time. The overall

patterns for a given critical task show fairly consistently that the

average time to perform a task diminishes as crew size increases.

The obvious exceptions are for Victim (#1 and #2) Rescue and

Descent, since the same number of firefighters were carrying the

victim during these tasks regardless of overall crew size. Note the

cascading start times by crew size for the early critical tasks ­­

Advance Attack Line, Advance Second Line, Fire Out, Search and

Rescue, and Victim Found. Note also that the time differentials by

crew size are very pronounced for both victim rescues. With

shorter durations of these critical tasks for larger crew sizes, the

net result is seen in the right hand side of the graph — All Task

Complete times are substantially reduced for crew size of 6

compared to 5, 5 compared to 4, etc. The greatest improvements

in All Task Complete time occurred for time differences between

3­person and 4­person crews and between 4­person and 5­person

crews.

9.5 Search Buttons

The data generated from the search button presses provided

time­based firefighter location information. This information

gave insight into the effects of crew size changes and, when

applicable, crew­splitting. Figure 61 shows the search time­history

of a 3­person crew that used the stairs. The horizontal axis

represents time, where the initial time is the start of the

experiment. The vertical axis represents the button numbers. In

Figure 61, the circles represent buttons that existed on the interior

search loop (buttons #1­9) and the diamonds represent buttons

Figure 61: Button presses as a function of time on the fire floor for a

3­person crew using the stairs.

22 24 26 28 30 

2 

4 

6 

8 

Floor 10 Inside Loop 

Time (minutes) 

Button Number 

35 40 45 50 55 

10 

15 

20 

Floor 10 Outside Loop 

Time (minutes) 

Button Number 

0 10 20 30 40 50 60 70 

5 

10 

15 

20 

Time (minutes) 

Button Number

Inside Loop 

Outside Loop 

on the outer search loop (buttons #10­24). The top left plot shows

only the inside search loop buttons pressed whereas the top right

plot shows only the outside search loop buttons pressed. The

bottom plot is the combined inside and outside search data.

Examination of the button data as a function of time shows that

there were distinct periods of time when no buttons were pressed.

These extended time gaps represent an exchange of crews (one

crew reported to Rehab, while another crew was dispatched from

Staging and began searching where the other left off). As

mentioned previously, a crew change occurred if the searching

crew ran out of air, reached the end of a tag line, or found a

victim. Due to the distinct inside and outside search loops, a

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detailed analysis of the button data in this report will be focused

on the fire floor.

For a 3­person crew, the first button press occurred

approximately 21 min into the experiment, as indicated in Figure

61 (refer to button locations in Figure 31). The first­in truck

company (Truck 1) searched the fire floor until button 8 was

pressed at approximately 24 min. Between presses of button 8 and

button 9, there was an extended gap in time of approximately 6

min. This gap represents a crew change as Truck 1 either reached

the end of the search rope or exceeded their time on supply air.

The second truck assigned to the search picked up where the first

truck company left off; their first button press was button 9.

Because button 9 represents completion of the interior search, the

second­in truck started the search of the outer loop, pressing

buttons 10 and 11. This is shown in both the top right and

bottom figures. The time gaps between the button presses of 11

and 12 as well as 18 and 19 indicate that two more crews were

required to complete the search of the fire floor. For this

particular experiment, four 3­person crews were required to

complete the search.

Similar examination of the fire floor button data for all of the

crew size configurations can be used to determine how many

crews were needed to complete search and rescue operations.

Table 6 shows the average number of crews required to complete

the search operations for each crew size examined in the

experiments. This average number of required crews was

calculated by including high and low deployments as well as stair

and elevator ascents.

Crew Si e

3-person

Average Number

of Crews to Complete

Search on Fire Floor*

4

Total Number of

Firefighters Actively

Searching the Floor

11

4-person 3 11

5-person 2 9

6-person 2 11

* Rounded to the nearest whole number of crews

Table 6: Average number of crews required to complete search and

rescue on the fire floor for each crew size

Table 6 shows that as the crew sizes increased from 3­person to

4­person, the average number of crews required to complete the

search decreased from 4 to 3. The drop in number of crews

between 3­person and 4­person crews was a result of

crew­splitting for the second­in truck crew. The 4­person crew on

the second­in truck could split into two groups of two firefighters

to concurrently complete the search on the inside search loop and

begin searching the outside loop. This result is shown in Figure

62.

Figure 62 shows that the first­in truck company was able to hit

the first 5 buttons before leaving the fire floor for relief. Though

technically a 4­person crew, one firefighter remained in the lobby

to pressurize the stairwells with PPV, leaving 3 to ascend for

search activity. Therefore, the first­in truck company was really a

3­person crew and could not split into two teams. The second­in

truck company, however, ascended to the fire floor as a full

Figure 62: Button presses as a function of time on the fire floor for a

4­person crew using the stairs

25 30 35 

2 

4 

6 

8 

Floor 10 Inside Loop 

Time (minutes) 

Button Number 

40 45 50 55 

10 

15 

20 

Floor 10 Outside Loop 

Time (minutes) 

Button Number 

0 10 20 30 40 50 60 70 

5 

10 

15 

20 

Time (minutes) 

Button Number

Inside Loop 

Outside Loop 

4­person crew. They were able to split and search the inside loop

and the outside loop, as shown by the bottom plot. Two firefighters

resumed searching the inside loop (button 6) and were able to

complete the loop (button 9). The remaining two firefighters

started searching the outside loop and reached the victim (button

18). A third crew completed the remaining length of the outside

loop. A full complement of 4­person crews was able to complete

the search using fewer crews than a complement of 3­person

crews, because of the ability to split crews into two teams during

the search. The advantages of splitting crews were even more

evident in the 5­person and 6­person crews because the first­in

trucks arrived on the fire floor with a working 4­person and

5­person crew, respectively. This allowed both initial crews to split

and begin searching the inside and outside loops simultaneously

upon arrival. Figure 63 and Figure 64 show the button history of

5­person and 6­person crews that used the stairs.

Figure 63: Button presses as a function of time on the fire floor for a

5­person crew using the stairs

18 20 22 24 26 28 

2 

4 

6 

8 

Floor 10 Inside Loop 

Time (minutes) 

Button Number 

20 25 30 

10 

15 

20 

Floor 10 Outside Loop 

Time (minutes) 

Button Number 

0 10 20 30 40 50 60 70 

5 

10 

15 

20 

Time (minutes) 

Button Number

Inside Loop 

Outside Loop 

67
                 

               

                   

                     

               

                   

       

                 

                 

                 

                   

                   

                   

                   

                   

                 

                     

                       

                       

                     

                   

             

                         

                       

                 

                 

                       

                       

                 

               

                     

               

                 

                   

               

                   

                   

             

               

                 

             

           

             

             

                           

       

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Figure 64: Button presses as a function of time on the fire floor for a

6­person crew using the stairs

18 20 22 24 26 28 

2 

4 

6 

8 

Floor 10 Inside Loop 

Time (minutes) 

Button Number 

20 25 30 35 

10 

15 

20 

Floor 10 Outside Loop 

Time (minutes) 

Button Number 

0 10 20 30 40 50 60 70 

5 

10 

15 

20 

Time (minutes) 

Button Number

Inside Loop 

Outside Loop 

Table 6 shows that both the average 5­person and 6­person

crews are more time­efficient, requiring the same number of

crews (one less than 4­person crews) to complete the fire floor

search. Figure 63 and Figure 64 show that both crew sizes could

initially split, so the differences between the 5­person and

6­person crews were due to the additional firefighter on the search

crew searching the outer loop.

The button data provided insight into the total time actively

spent searching, which the timer data did not. Timer data

provided information on the duration of the search and rescue

actions; however, that time also included all of the gaps associated

with crew changes. Using the button data, these time gaps could

be subtracted from the total search duration time to determine an

active search time. The active search time was defined to include

the entire time a particular crew spent searching the floor. For

example, consider Figure 63 for the 5­person crew. The bottom

plot shows that the first crew was split into two subgroups to

search the inner and outer loop at the same time. The upper two

plots show that the first button pressed was button 1 on the inside

loop. The last button pressed was button 18 on the outside loop.

Therefore, the time spent actively searching was the length of time

between those button presses. This analysis was independent of

when the first crews arrived on the floor or the length of time it

took for a relief crew to arrive. Therefore, it allowed for the effects

of both deployment size and ascent method to be examined

together. Table 7 shows the average time spent actively searching

the fire floor by each crew size and the standard deviation of the

time measurements.

Similar to Table 6, this table shows that there was a gain in

performance when crews can split. Most notably, the largest gain

occurred between 4­person and 5­person crews. As stated earlier,

a 5­person crew was large enough to split the first­in crew. Time

spent actively searching by the 5­person and 6­person were

nominally the same. Differences here are again attributed to the

extra firefighter on the outer loop. The fire floor button data

showed that because of crew splitting, 5­person and 6­person

crews required the lowest number of crews to complete the search

and spent the least amount of time actively searching the floor.

9.6 Measurement Uncertainty

The measurements of length and time taken in these

experiments have unique components of uncertainty that must be

evaluated in order to determine the significance of the results.

Appendix F summarizes the uncertainty of key measurements

taken during the experiments. Importantly, the magnitudes of

uncertainties associated with these measurements have no impact

on the statistical inferences presented in this report.

Crew Si e

3-person

Average Time of

Active Searching on

Fire Floor (MM:SS)

15:28

Standard Deviation

of Active Searching

on Fire Floor (MM:SS)

3:19

4-person 14:26 2:51

5-person 9:59 1:55

6-person 9:57 2:08

Table 7: Average and standard deviation of time spent actively

searching the fire floor as a function of crew size

68
       

       

        

         

           

          

     

         

              

           

       

        

              

           

             

             

         

          

         

       

      

         

         

         

         

         

             

     

           

         

       

       

           

     

10. Time­to­Task Results
 

10.1 How to Interpret

Time­to­Task Graphs

Figure 65 presents a sample

time­to­task analysis. Each crew size

has a column graphic showing the

start time and completion time for the

task. Visually, columns starting lower on

the graph depict deployment

configurations that resulted in earlier start

times. The height of the column graphic is

a visualization of the duration of the task,

with taller columns indicating longer

times­to­task completion. Times are also

shown in a table below the graph. If

subtracting the start time from the end

time yields a result that differs from the

printed duration by one second, it is the

result of rounding fractional seconds to

the nearest whole second. Where vertical

response mode or alarm size were

statistically significant, the effects are

graphed separately. All differential

outcomes described in this chapter are

statistically significant at the 95 %

confidence level or better. Where time

differences due to vertical response mode

or alarm size were not statistically

significant, as in this sample, the data were

combined by crew size.

Time is represented on the y­axis with

0:00:00 denoting fire ignition time. (See

Table 4 and Figure 33.)

Unless otherwise stated, differences are
 

for end times of the relevant task.
 

Figure 65: Sample time­to­task graph

69
10.2 Overall Time to Task

Completion and Crew Size Three-Person Start and End Times of Critical Tasks

Overall scene time is the time that 1:10:00

firefighters are actually engaged in tasks on

the scene of a structure fire and are 1:00:00 unavailable for dispatch to other incidents.

The times noted do not include some tasks

such as salvage, overhaul and secondary

search of the structure as these were not

included in the field experiments.

The graphs in Figure 66 through Figure

69 show average times for each critical task

by crew size. Percentage calculations for all

the charts were based on the overall time

from detection of the incident to the

completion of all on­scene tasks. Time to

detection, call processing time, and travel aT sk Time From Initiation to Completion 0:50:00

0:40:00

0:30:00

0:20:00

0:10:00

time may vary across jurisdictions. The

times used in this report are considered 0:00:00

conservative.  

Figure 66: Average start and end times of critical tasks for a 3­person crew

Four-Person Start and End Times of Critical Tasks

1:10:00

aT sk Time From Initiation to Completion1:00:00

0:50:00

0:40:00

0:30:00

0:20:00

0:10:00

0:00:00

Figure 67: Average start and end times of critical tasks for a 4­person crew

70
Five-Person Start and End Times of Critical Tasks

1:10:00

aT sk Time From Initiation to Completion1:00:00

0:50:00

0:40:00

0:30:00

0:20:00

0:10:00

0:00:00

Figure 68: Average start and end times of critical tasks for a 5­person crew

Six-Person Start and End Times of Critical Tasks

1:10:00

aT sk Time From Initiation to Completion1:00:00

0:50:00

0:40:00

0:30:00

0:20:00

0:10:00

0:00:00

Figure 69: Average start and end times of critical tasks for a 6­person crew

71
     

               

         

               

             

         

         

           

               

       

           

     

                 

           

               

         

       

         

                   

     

                 

           

             

             

             

               

   

       

       

               

               

           

         

       

             

               

             

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10.3 Advance Attack Line

Putting water on the fire is one of the Advance Attack Line 

most important tasks on the fireground. 1:10:00 

Before water can be put on a fire however,

a hose line must be stretched from the

1:00:00 standpipe in the stairwell to the

compartment where the fire is burning.

aT sk Time From Initiation to Completion 

Figure 70 measures the interval from the

start to the end of the task Advance Attack

Line.

The time differences increased with

increasing crew size. From the initiation of

on­scene firefighting activities, 4­person

crews were 1 min 42 s (8.5 %) faster than

3­person crews to stretch the hose line.

Five­person crews were 2 min 47 s (13.9 %)

faster than 3­person crews. The most

0:50:00 

0:40:00 

0:30:00 

0:20:00 

0:10:00 

notable comparison is between 6­person

crews and 3­person crews. The 6­person

crews were 4 min 28 s (22.3 %) faster in task

completion time.

10.4 Advance Second Line

The size of the fire required two 2 1⁄2 inch

lines to fully suppress, therefore a second

hose line had to be advanced from the

standpipe in the stairwell to the fire. Figure

71 measures the interval from the start of

the task Advance Second Line to the end of

this task.

From the initiation of on­scene

firefighting activities, 5­person crews were

4 min 4 s (17.4 %) faster than 3­person

crews and 2 min 43 s (12.3%) faster than

4­person crews to stretch the second line.

Finally, the most notable comparison was

between 6­person crews and 3­person

crews. The 6­person crews were faster by 5

min 38 s (24.1 %) in task completion time.

0:00:00 

3-Person 4-Person 

nd TE ime 0:20:03 0:18:21 

Duration 0:02:46 0:02:27 

Start Time 0:17:17 0:15:54 

Figure 70: Advance Attack Line on Fire Floor

5-Person 6-Person 

0:17:16 0:15:35 

0:02:26 0:01:59 

0:14:50 0:13:36 

Figure 71: Advance Second Line on Fire Floor

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1:10:00 

Fi OutreFi

10.5 Fire Out

Extinguishing the fire out is critical to

reducing risk to both firefighters entering

the structure and to occupants. Fire Out,

in the study, was defined as having both

the attack line and the second hose line in

place. As shown in Figure 72, the 4­person

crews were 2 min 14 s (8.1 %) faster in the

Fire Out time compared to 3­person crews.

The 5­person crews were 1 min 15 s (5.0

%) faster than 4­person crews and 3 min

29 s (12.7 %) faster than 3­person crews.

The 6­person crews finished 7 min 2 s

(25.6 %) faster than the 3­person crews.

aT sk Time From Initiation to Completion 

1:00:00 

0:50:00 

0:40:00 

0:30:00 

0:20:00 

0:10:00 

0:00:00 

3-Person 4-Person 5-Person 6-Person 

nd TE ime 0:27:26 0:25:12 0:23:57 0:20:24 

Duration 0:10:09 0:09:18 0:09:06 0:06:53 

Start Time 0:17:17 0:15:54 0:14:50 0:13:31 

Figure 72: Fire Out

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10.6 Search and Rescue 10th Floor

The fire floor in the experiments

measured 30,000 sq ft (2800 m2) and

contained 96 cubicles. Figure 73

summarizes the amount of time that crews

took to start and complete the search on

the fire floor. The 4­person crew started

the search 1 min 23 s (7.8 %) faster than

the 3­person crew and completed the

search and rescue 11 min 21 s (18.4 %)

faster than the 3­person crews. The

5­person crews started the search 1 min 4 s

(6.7 %) faster than the 4­person crews and

2 min 27 s (14.1 %) faster than the

3­person crew. Additionally, 5­ person

crews completed the search faster than the

4­ and 3­person crews by 13 min 34 s (26.8

%) and 24 min 55 s (40.3 %) respectively.

Six­person crews had the best times,

starting the search 1 min 19 s (8.8 %)

faster and completing the search 2 min 57

s faster than 5­person crews (8.0 %). The

greatest difference in search times was

between 6­ and 3­person crews. Six­person

crews started the search on the fire floor 3

Figure 73: Search and Rescue on Fire Floor (10th) min 46 s (21.7 %) faster and completed the

search 27 min 51 s (45.0 %) faster than the

3­person crews.

73
             

 

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10.7 Victim #1 Found

There was a single victim located on the

fire floor that was found and rescued by all

crews. Figure 74 shows the time taken by

crews to locate the victim on the fire floor.

A 5­person crew operating in the high­rise

structure located the victim 25 min 18 s

(50.6 %) faster than a 3­person crew and

12 min 7 s (32.9 %) faster than a 4­person

crew. A 6­person crew located the victim

on the fire floor 28 min 33 s (57.1 %)

faster than the 3­person crew, 15 min 21 s

(41.7 %) faster than the 4­person crew,

and 3 min 14 s (13.2 %) faster than a

5­person crew.

Figure 74: Victim #1 Found on Fire Floor

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10.8 Victim #1 Rescue

Since the experiment protocol dictated

that each victim be rescued by two

firefighters, one at the shoulders and one

at the legs, the duration of the victim

rescue varies only slightly as seen in Figure

75. However, the start and end time of

victim rescue is significantly different

between crews. Four­person crews

removed the victim from the IDLH

environment 13 min 11 s (25.1 %) faster

than a 3­person crew. Likewise, 5­person

crews were able to remove the victim from

the fire environment 11 min 39 s (29.7 %)

faster than the 4­ person crews while

6­person crews removed the victim from

the environment 14 min 58 s (38.1 %)

faster than the 4­person crews and 3 min

19 s (12.0 %) faster than the 5­person

crews.

Figure 75: Victim #1 Rescue — Removed from IDLH atmosphere

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10.9 Victim #1 Descent

Experiment protocols required that an

EMS crew of two carried the victim out of

the building. Each crew was to descend via

stairs or elevator depending on the

scenario being tested, so duration times

did not vary greatly between overall crew

sizes studied as shown in Figure 76. The

start and end times of this task did vary.

Four­person crews were able to facilitate

the victim descent and exit from the

building 11 min 59 s (21.5 %) faster than

3­person crews. Five­person crews were

able to facilitate victim descent 11 min 39 s

(27.5 %) faster than 4­person crews and 24

min 1 s (43.1 %) faster than 3­person

crews while 6­person crews were 3 min

and 19 s faster than 5­person crews (11.0

%). Additionally, victim descent occurred

4 min 42 s more quickly for crews using

the elevator rather than the stairs.

Figure 76: Victim #1 Descent

10.10 Advance Line Above the Fire

Advance Line Above Fire (11th Floor)

1:10:00 In a high­rise structure, it is essential to

aT sk Time From Initiation to Completion 

1:00:00 

0:50:00 

0:40:00 

0:30:00 

0:20:00 

0:10:00 

0:00:00 

3-Person 4-Person 5-Person 6-Person 

place a hose line on the floor above the fire

floor to fight potential vertical fire spread.

Figure 77 measures the interval from the

start of the task Advance Line Above the

Fire to the end of this task. Comparing

crew sizes, 5­person crews were 2 min 58 s

(11.5 %) faster than a 3­person crew to

complete the same task. The most notable

comparison was between 6­person crews

and 3­person crews. The 6­persons crews

were 3 min 37 s (14.0 %) faster in task

completion time.

nd TE i

Durati 

Start T 

me 0:25: 

on 0:02: 

ime 0:22: 

50 0: 

55 0: 

56 0: 

24:44 

02:03 

22:41 

0:22:52 

0:01:50 

0:21:03 

0:22:13 

0:01:26 

0:20:47 

Figure 77: Advance Line on Floor Above the Fire (11th)

75
         

           

           

             

           

           

           

             

         

         

               

       

             

             

               

             

         

                 

         

                 

     

               

             

             

           

             

             

             

       

                 

               

           

             

                 

     

                   

 

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10.11 Search and Rescue 11th Floor

The floor above the fire was separated

into a number of conference rooms and

offices that had to be searched by each

crew. The area of the floor measured

30,000 sq ft (2800 m2). Figure 78

summarizes the times that crews took to

start and complete the search on the floor

above the fire. During the experiments, the

4­person crews completed the search 9

min 31 s (18.6 %) faster than the 3­person

crews. Meanwhile, the 5­person crews

started a primary search/rescue 1 min 34 s

(6.8 %) faster than the 4­person crews and

completed the search 2 min 37 s (6.3 %)

faster than the 4­person crews. In the same

structure, the 6­person crews also started

the search 1 min 30 s (6.6 %) faster than

the 4­person crews but completed the

search 5 min 8 s (12.3 %) faster than the

4­person crews.

Figure 78: Search and Rescue on Floor Above the Fire (11th)

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0: 5838:

0: 4617:

0: 1221:

2836:0:

1215:0:

1521:0:

10.12 Victim #2 Found

In addition to the victim on the fire floor,

a second victim was located on the floor

above the fire. Each crew operating on this

floor was tasked with locating and rescuing

the victim. Figure 79 shows the times when

crews located the victim on the floor above

the fire. A 5­person crew operating in the

high­rise structure located the second

victim 17 min 23 s (34 %) faster than a

3­person crew and 2 min 41 s (7.4 %)

faster than a 4­person crew. A 6­person

crew located the second victim on the floor

above the fire 2 min 48 s (7.7 %) faster

than the 4­person crew.

Figure 79: Victim #2 Found on Floor Above the Fire

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aT sk Time From Initiation to Completion 

Victim #2 Rescue - 11th Floor 

1:10:00 

1:00:00 

0:50:00 

0:40:00 

0:30:00 

0:20:00 

0:10:00 

0:00:00 

3-Person 4-Person 5-Person 6-Person 

10.13 Victim #2 Rescued

Since the experiment protocol dictated

that each victim be rescued by two

firefighters, one at the shoulders and one

at the legs, the duration of the rescue of

Victim #2 varies only slightly by crew size

as seen in Figure 80. However, the start and

end time of victim rescue is significantly

different between crews due to

performance on previous tasks.

Four­person crews removed Victim #2

from the IDLH environment 14 min 33 s

(27.2 %) faster than a 3­person crew.

Five­person crews were able to remove

Victim #2 from the fire environment 17

min 9 s faster (32.1 %) than 3­person

crews and 2 min 36 s faster than the

4­person crews (6.7 %). Similarly, the

6­person crews rescued the victim 2 min

48 s (7.1 %) faster than 4­person crews.

End iT me 0:53:28 0:38:55 0:36:19 0:36:08
 

Duration 0:02:22 0:02:31 0:02:36 0:02:32
 

Start Time 0:51:06 0:36:25 0:33:43 0:33:36
 

Figure 80: Victim #2 Rescued from Floor Above the Fire

10.14 Victim #2 Descent

Victim #2 Descent As with Victim #1, experiment protocols

required that an EMS crew of two carried 1:10:00 

aT sk Time From Initiation to Completion 

1:00:00 

0:50:00 

0:40:00 

0:30:00 

0:20:00 

0:10:00 

0:00:00 

3-Person 4-Person 5-Person 6-Person 

the victim out of the building. Each crew

was to descend via stairs or elevator

depending on the scenario being tested, so

duration times did not vary greatly

between overall crew sizes studied as seen

in Figure 81. The start and end times of

this task did vary. Five­person crews were

able to facilitate the victim descent 2 min 4

s (4.8 %) faster than 4­person crews and

17 min 1 s (29.4 %) faster than 3­person

crews. Six­person crews were able to

facilitate victim descent 3 min 21 s (7.8 %)

faster than 4­person crews. Additionally,

victim descent occurred nearly 6 min more

quickly for crews using the elevator rather

than stairs.

nd TE ime 0:57:54 0:42:57 0:40:53 0:39:35 

Duration 0:03:06 0:02:34 0:02:44 0:02:05 

Start Time 0:54:48 0:40:23 0:38:09 0:37:30 

Figure 81: Victim #2 Descent

77
   

           

         

             

       

             

           

         

             

           

         

           

             

     

         

   

         

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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10.15 Simultaneous Operations

by Crew Size

The 38 fireground tasks included in the

experiments were completed by all crews

regardless of crew size. However, as on an

actual fireground, assignments of crews

and the tactics used on each task varied

based on the availability of firefighters to

complete the task. For example, search

patterns used on the fire floor and floor

above the fire were dependent on the

number of firefighters available on the

crew assigned to complete the task. Figure

82 through Figure 85 show how tasks were

simultaneously or sequentially performed

based on the number of firefighters

available on scene.31

Figure 82: 3­person crew task operation

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Figure 83: 4­person crew task operation

31.A =Ambulance, E = Engine,T= Truck

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Figure 85: 6­person crew task operation

79
     

                   

                 

                   

                    

                        

                 

                   

                  

                          

                 

                          

               

                       

                     

                   

                             

                     

             

                       

                     

               

                     

                       

                 

                     

                 

                     

     

                   

                  

                   

                   

                         

                 

           

                

                 

             

                 

                   

                     

                       

                      

                 

          

         

                   

                     

               

                     

                   

                   

                   

               

                           

                 

                 

10.16 Summary of Regression Results

Crew Size

Appendix C1 uses the results of regression analysis to show the

incremental effects of crew size on critical tasks. Time increments

analyzed include the begin time, duration and end time of each

critical task. The results control for alarm size and ascent mode,

so the results indicate the net impact of crew size change alone.

Generally, going from 3­person to 4­person crews had a large

impact on begin time to advancing the attack line, advancing the

second line, and starting search and rescue. Time reductions were

in the range of 1 min to 2 min. Going from 4­person to 5­person

crews showed significant time reductions in begin times all critical

tasks in the range of 1 min to 2 min. Increasing crew size from

5­person to 6­person crews showed a significant reduction, just

over 1 min, in the begin time to advance the attack and second

lines and for search and rescue on the fire floor (10th floor).

When assessing task end times and incrementing crew size by a

single firefighter (i.e., 3 to 4, 4 to 5, and 5 to 6), the largest time

improvements are seen when going from crew size 3 to 4. As

firefighter crews navigate the later tasks, the improvements reach

the 10 min to 15 min range.Very large improvements are seen for

the 10th Floor Search and Victim #1 Rescue tasks (over 11 min)

when incrementing crew size from 4 to 5. The improvements in

All Tasks Complete end times are substantial (9 min to 12 min)

when incrementing crew size from 3 to 4 or from 4 to 5.

Increasing crews by 2 firefighters resulted in an even larger

reduction in task times. Increasing from 3 to 5 firefighters or from

4 to 6 firefighters per crew showed the largest improvements in

begin times for critical tasks, ranging from 1 min to 25 min.

Fire Service Access Elevators

All Tasks Complete occurred over 4 min more quickly when the

elevators were utilized compared to stairs. Begin times for nearly

every task above ground level and nearly all end times were

reduced compared to stair ascent. Most of the reductions due to

elevator usage were in the 2 min to 4 min range, with a few

obvious exceptions in that using fire service access elevators more

dramatically reduced times associated with upward and

downward transport of people or equipment. Using elevators to

transport air bottles and other equipment from the lobby to

Staging allowed completion of Establishment of Stairwell Support

over 10 min more quickly than moving the equipment manually

up the stairs. Additionally, the transport of both Victim #1 and

Victim #2 from Staging to the outside of the building was faster

when using the elevators (compared to the stairs), by 2 min 41 s

and 3 min 19 s, respectively. As a result, except for Establishment

of Stairwell Support and Victim Descent, there were no ascent

mode differences for task duration.

Combining Alarm Size and Ascent Mode

The results of regression analysis to compare high and low alarm

size and to compare elevator to stairs ascent for all critical tasks

and associated outcomes are presented in Appendix C2. Because

alarm size and ascent mode are design factors built into the field

experiment in order to examine crew size effects, a summary of

the findings in this section is provided rather than a detailed

assessment. With regard to alarm size, five of the eight significant

differences between high and low alarm sizes involved reductions

of task end times ranging between 1 min and 3 min in favor of the

high alarm size response. These tasks were Primary Search of

Figure 86: All Tasks Complete comparing all three study variables

80
                     

         

           

                       

                 

               

                     

                 

                               

               

                         

                 

                 

                   

                   

                 

           

         

                     

                   

               

                   

                 

                     

                       

           

               

                     

                  

               

                   

               

                 

                     

                        

                   

               

                     

                    

                       

                

                       

                     

                           

                 

                       

                 

               

                 

                   

                     

                     

                       

                       

                     

                 

                     

                     

                 

                 

         

                            

                         

                     

     

Floor 11, the three rescue tasks related to Victim #2 (Find, Rescue,

Descent), and Advancing Line Above Fire.

Comparing elevator to stair ascent, statistically significant

reductions in time were seen in favor of elevator use for over two

thirds of the critical task outcomes. The most sizeable time

reduction for the elevator was for Establishing Stairwell Support,

with reduction of nearly 10 min in duration and end time. Other

notable reductions in favor of elevator use were for Victim

Descent at 4 min 42 s for Victim #1 and 5 min 30 s for Victim #2.

When other significant reductions occurred they were smaller, in

the range of about 1 min to 4 min (see Appendix C2 for details).

The assessment of alarm response and ascent mode confirmed the

logical direction of differences (i.e., high alarm size faster than

low, elevator faster than stairs) when they were found to exist.

A visual comparison of All Tasks Complete for all three study

variables: crew size, ascent mode (stairs vs. elevators), and alarm

size is presented in Figure 86.

Combining Alarm Size and Crew Size

Given the findings from the crew size analysis that adding one or

two firefighters to a crew could on average achieve substantial task

time decreases, a logical question is whether the meaningful

benefits of a higher crew size could be realized by implementing a

higher alarm response at a smaller crew size (e.g., high/4

compared to low/5). The hope might be that a high response with

lower crew size would yield similar results in task timing to that of

a low response with higher crew size.

Appendix C3 presents regression results that compare the effect

of high response with lower crew size compared to a low response

with higher crew size. These results were also compiled in

separate summary tables for begin, duration, and end times.

Appendix D Table 20 provides a summary of findings for begin

times of critical tasks. The analysis shows that statistically

significant differences in begin times occurred for a low alarm

response with 4 or 5 crew size compared to high response with

crew sizes of 3 and 4, respectively. As seen in Figures 87 through

89, there are significant reductions in begin times for all critical

tasks from Advance Attack Line through Victim #1 Descent.

Sizeable reductions of about 12 min are also seen for Victim #2

Rescue and Descent. This suggests that a low alarm response with

crews of size 4 or 5 outperforms a high response with crew sizes

smaller by one firefighter. When significant decreases occur, they

are in the range of 1 min to just under 2 min.

It is noteworthy that this pattern does not hold for low response

with a crew size of 6 compared to high response with a crew size of

5. The observed differences in begin times were significantly higher

for Primary Search of Floor 11 and Advance Line Above Fire.

Figure 87 through 89 also provide a graphical summary of

findings for tasks deemed critical for duration times. Although

less than a third of the comparisons were statistically significant,

when they occurred, they tended to be prominent. For Search of

the 10th Floor and Victim #1 Rescue, a low response with crew

size 4 showed about 11 min to 13 min reductions compared to

that of a high response with crew size 3. And for low response

with crew size 5, the duration time reductions were 10 min to 13

min compared to a high response with crew size 4. The low/4

combination revealed an 8 min reduction in duration time for

Primary Search of Floor 11 and about a 12 min reduction for

Victim #2 Rescue compared to a high response with crew size 3.

Similarly large reductions in duration time appear for All Tasks

Complete under these two response crew size scenarios. The low/6

combination shows three significant duration reductions

compared to high/5: a 2 min 12 s reduction for Fire Out and a

2 min 30 s reduction for Primary Search of Floor 11, and 1 min

reduction for Victim #2 Descent. (See Table 21 in Appendix D for

a summary of findings.)

81
Finally, Figures 87 through 89 present

critical task contrasts of low alarm size to 3 High vs 4 Low Comparison Start and End Times of Critical Tasks

that of a high alarm size with one less crew

on staff. Over half of the task end time

comparisons were statistically different

when comparing the low/4 and low/5

combinations against their counterparts o oC

mp t el oi n

1:10:00

1:00:00

0:50:00

(i.e., high/4 and high/5, respectively).

When significant, low alarm size with crew

sizes 4 and 5 displayed end time reductions

of 2 min to over 14 min. The low/4

combination showed significant end time

reductions compared to high/3 for 11 of

the 14 critical tasks in this analysis. For the ksaT e mi T From nI oit aiti n T

0:40:00

0:30:00

0:20:00

0:10:00

0:00:00

low/5 combination, 6 of 14 tasks showed

significant reductions in end time

compared to high/4. Only 2 of 14 tasks

exhibited significantly lower end times for

the low/6 combination relative to that of

high/5. Generally, for critical task end

times, reductions were most pronounced

when comparing low/4 to high/3, followed

by low/5 compared to high/4. The low/6

combination featured the smallest

3-High 4-Low

Figure 87: Comparison of 3 high/4 low start, end, and duration times

3 4 High vs 45 Low Comparison Star t and End Times of C ritical Tasks

reductions compared to the high/5. (See

Appendix D Table 22 for a summary of

end time analysis.)

o oC p m oit el n

1:10 :00

1:00 :00

0:50:00

0:40 :00

0:30 :00

0:20 :00

0:10:00

0: 00:00

ksaT e mi T From nI noit aiti n T

4-High 5-Low

Figure 88: Comparison of 4 high/5 low start, end, and duration times

5 3 High vs 64 Low Comparison Star t and End Times of C ritical Tasks

o oC p m oit el n

1:10 :00

1: 00:00

0:50 :00

0:40 :00

0:30 :00

0:20 :00

0:10 :00

0: 00:00

ksaT e mi T From nI noit aiti n T

5-High 6-Low

82 Figure 89: Comparison of 5 high/6 low start, end, and duration times
                   

                 

                   

                    

                   

                   

     

         

             

                   

    

               

                 

           

                 

               

                 

                     

                      

                        

                      

     

         

                     

                   

                     

                     

                   

                         

                 

   

In summary, the analysis of the alarm response and crew size

combinations suggests that the benefits of crew size increases (in

terms of reduced begin, duration and end times for critical tasks)

are fairly robust. Low alarm response with a higher crew size

tends to be more favorable in critical task timings than the

corresponding timings for a high alarm response with a crew size

of one less firefighter.

Combining Alarm Response and Ascent Mode

Appendix C4 presents regression results that compare several

combinations of alarm size, (high or low) and ascent mode (stairs

or elevator).

n Stairs/High vs. Stairs/Low; this scenario focuses on stair ascent

and examines the impact of high versus low alarm size;

n Elevator/High vs. Elevator/Low; this scenario focuses on

elevator ascent and explores the effect of high versus low

alarm size.

Stairs/High vs. Stairs/Low ­ The alarm size had virtually no

effect for critical task timings, with the exception of Primary

Search of the Floor Above the Fire (Floor 11) and Victim #2

Rescue. High alarm size realized a mean reduction in the range of

1 min to 4 min for these tasks. All Tasks Complete was also

significantly shorter for high alarm size by 3 min. No other task

timing comparisons were statistically different.

Elevator/High vs. Elevator/Low — In the elevator scenarios,

high alarm size led to eight significantly lower timings than did a

low alarm response. Results showed 45 s reductions in begin time

for Fire Out, Primary Search of Fire Floor 10, and Victim #1

Found. Small reductions of just over 1 min were noted in begin

times for Search and Rescue 11th floor and Victim #2 Found.

Small reductions of 30 s to 2 min were also noted for times related

to Advance Line Above Fire. No other task timing comparisons

were statistically different.

83
   

       

                 

               

                 

                     

                 

                 

                 

                   

             

                   

     

           

               

     

                 

                   

         

               

                 

         

                   

                       

               

               

               

                 

             

     

         

                 

                   

                 

                     

                 

               

               

                 

           

               

                   

                   

             

               

                     

                 

             

                 

                  

                   

                        

                       

                   

                   

                   

               

                   

             

                     

                   

                 

           

             

                     

                         

                 

               

                 

               

                   

                   

       

       

 

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11. Fire Modeling
 

11.1 Purpose of Fire Modeling

The time to task data from the firefighter exercises provided

critical data regarding the timing of key fireground tasks.

However, as the high­rise building could not accommodate live fire

tests, there was no experimental data on the tenability of the fire

floor for each of the different response configurations. To couple

thermal and tenability issues associated with real fire behavior to

the experimental time to task data, a computer fire model was

used. An advantage of using a computer model is that the

hazardous conditions can be simulated, thereby minimizing the

risk to the safety of the firefighters, timers, and other personnel

present during exercises.

11.2 Research Question: Time to Untenable Conditions

More specifically, computer fire modeling was conducted to assess

the following research questions:

Fire Modeling Research Questions

1) How do performance times resulting from different

combinations of crew si e, alarm si e vertical

ascent, and fixed fire sprinkler systems affect the

development of standard fire growth scenarios?

2) How do crew si e, alarm si e, vertical ascent, and

fixed fire sprinklers affect the resulting interior

tenability on the fire floor?

The quantitative methods used to generate the analytic data for

this portion of the high­rise research study are discussed below.

11.3 The NIST Fire Dynamics Simulator

The computational model selected for the analysis in this project

is the NIST Fire Dynamics Simulator (FDS). FDS is a

physics­based computational fluid dynamics program with an

emphasis on smoke and heat transport from fire (McGrattan et al.

2012). The version of FDS used for the simulations in this report is

FDS 6 RC1 (sub­version #13844). The visualization component to

FDS is Smokeview. Smokeview allows users to visualize the

three­dimensional environment created by FDS as well as the data

generated by the model in two and three dimensions when

applicable. Smokeview Version 6.0.11 (sub­version #14315) is used

for this report.

Tenability Due to Fire Gases

FDS is used to calculate the change in interior conditions

(spatially and temporally) of the high­rise due to the presence of

fire. This analysis focuses on the tenability (the likelihood that

persons exposed to a specific dose of toxic products will be capable

of escaping) of the fire floor. To characterize the accumulated

hazard associated with inhalation of gases typical of combustion

products, a time­integrated value known as the fractional effective

dose (FED) is used. FED is an international standard, maintained

by the International Standards Organization (ISO) and

documented in ISO document 13571. FED is a probabilistic

quantity used to estimate the impact of toxic gases on humans

(ISO 2007). For this study, FED includes the impact of excess

carbon monoxide and carbon dioxide inhalation and oxygen

depletion. Additional gases such as cyanide, nitric oxide and

irritants were not included in the calculation of the FED value as

they tend to be of secondary importance compared to carbon

monoxide, carbon dioxide, and oxygen.32 Depending on the fuels

present, neglecting these species may affect the FED for occupants,

potentially raising the FED value. Additionally, smoke density is a

commonly used tenability criterion, since it may limit the ability of

an occupant to find their way to an exit. However, it is assumed

for this analysis that occupants are in a single fixed location for the

duration of the fire event; therefore, smoke density is neglected.

FED values are generally divided by three thresholds as they relate

to the potential for certain portions of the population to become

incapacitated. There exists uncertainty in the correlation of FED

values and the percent of the population affected. See Appendix F

for uncertainty information. Incapacitation is defined to be the

point at which a person can no longer escape the hazardous area

on his/her own. The lowest FED threshold is 0.3, which typically

relates to the most sensitive populations: elderly, young, or those

with compromised immune systems. The lowest threshold group

encompasses approximately 11 % of the population. The second

threshold occurs at an FED value of 1.0, which represents the level

at which the median or 50 % of the population is likely to become

incapacitated. An FED value of 3.0 represents the upper threshold

for tolerance to combustion gas inhalation. This formulation of

FED assumes that the potential victim remains stationary over the

course of the simulation. Adding movement capabilities to FED

calculations is still under development. Table 8 shows the four bins

created by the three threshold limits and the percentage of the

population likely to become incapacitated.

FED Value matediEst FDS-Smokev ewi

Range Population Range oringlCo 

f Incapac ion tatio

0.0 < FED 0.3 0.0 < % 11 

0. F<3 ED 1.0 1 %<1 50 

1.0 < FED 3.0 50 < % 89 

FED > 3.0 % > 89 

Table 8: Relating FED values to percentage of population

likely to be incapacitated and indicating coloring scheme for

visualization.

32. From the ISO 13571 document: “All available evidence supports the working hypothesis that, in typical fire atmospheres,CO and HCN are the only asphyxiant combustion

products that exert a significant effect on the time available for escape.” However, oxygen is important if the levels fall below 13 %,while carbon dioxide levels above 2 % have a

hyperventilating effect that exacerbates the impact of CO uptake. HCN was neglected in this analysis due to the lack of reliable input data forthe model. These assumptions all

lead to an underestimate of the effects of the fire on occupants in this analysis.

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FDS and Smokeview can be used to calculate FED values as a

singular point in space, a two­dimensional plane, or

three­dimensional surfaces. In this report, FED values are

calculated for two­dimensional planes covering the entire 10th

floor at elevations of 3 ft (0.91 m) and 5 ft (1.5 m). To distinguish

between threshold levels within a plane, each range of FED values

has a unique color identifier. The third column in Table 8 shows

the colors used to identify each FED range. Note that FED is a

cumulative quantity. The FED value will continue to increase as

long as a potential victim remains exposed to hazardous

conditions. Even if the conditions return to ambient, the FED

value will remain constant at its peak for a significant period of

time or until the potential victim receives medical attention.

11.4 Development of the Design Fires

for FDS Simulations

A crucial element of computer fire modeling is the selection of a

design fire. A design fire curve quantifies how a fire grows and

decays over some pre­defined period of time (Hadjisophocleous

2008). For these experiments, the fire floor was configured to be

an open floor plan comprised of typical workspace cubicles;

therefore, a cubicle fire was determined to be the most likely fire

scenario.

Since fires were not an explicit part of the experiments,

determining the appropriate characteristics for the design fires

was paramount. The necessary design fire parameters are the fuel,

peak fire size, growth rate and duration. These parameters allow

for the construction of a design fire curve. One way to construct

the design fire curve is to use experimental data to determine

values for the critical parameters. In this report, two NIST reports

that documented experiments involving cubicle fires were used

(Ohlemiller et al. 2005, Madrzykowski et al. 2004).

While data from fire experiments provides validity to the

modeling calculations, not all fires grow at the exact rate observed

in the experiments. The growth rate of the fire is critical as it

significantly affects the hazard level faced by the occupants and

firefighters upon arrival to the fire floor; slower growing fires are

less hazardous upon arrival than faster growing fires. Therefore,

the design curve used in this high­rise study was idealized in two

ways: assuming three simple phases for the fire development, and

varying the growth rate to bound the problem. First, the Society

of Fire Protection Engineers (SFPE) Handbook describes three

basic phases to fire development: growth, steady burning, and

decay (Hadjisophocleous 2008). These phases can be clearly seen

in the experimental data shown in Figure 90 as the heat release

rate (HRR) increases to a peak, burns steadily for a period of time,

and then decays as the available fuel is consumed. Second, in

order to bound the range of hazards associated with potential

cubicle fires, three different t­squared fire growth rates were

chosen. For a t­squared growth rate fire, the change in HRR is

given by the square of time multiplied by a prefactor. By changing

the value of the prefactor from a small number (slow growth) to a

larger number (fast growth), the growth of the HRR can be

bounded. Slow, medium, and fast t­squared growth rate fires were

used as defined by the SFPE Handbook (Alpert 2008). The SFPE

Handbook defines the rates by the time it takes for the HRR to

reach 1 MW as shown in Table 9.

0 6 12 18 24 30 

0 

0.5 

1 

1.5 

2 

2.5 

3 

3.5 

Time (min) 

Heat Release Rate (MW) 

Cook County 

Slow 

Medium 

Fast 

Table 9: Time in minutes and seconds (MM:SS) for different growth

rates to reach specified HRR values.

t

2

 Fire Growth 

Rate 

Sprinkler Activation

Time (MM:SS) 

Figure 90: Heat release rate versus time curve of a typical single

cubicle fire from the Cook County Administration building compared

to design curves of slow, medium, and fast growth (Madrzykowski et

al. 2004).

Peak HRR Value 

(MW) 

Slow 4:54 0.41 

Medium 2:45 0.64 

Fast 2:15 1.69 

The three growth rates were used to simulate different degrees of

hazard, with HRR increased until it reached a maximum value.

This value was set at 75 % of the peak HRR value from the

experimental data, which was approximately 2.5 MW

(Madrzykowski et al. 2004). The HRR remained fixed at this peak

value until 70 % of the total energy in the fuel had been released.

At this point, the HRR began to decay linearly to 0 kW. These

thresholds were selected to best approximate the rate of energy

release by the experimental data, while still using simplified

design fire curves. Figure 90 shows the design curves for the slow,

medium, and fast growth rates compared to the experimentally

measured HRR data.

Note that according to Figure 90 the medium rate fire growth

curve is a high quality fit to the experimental HRR curve from

Madrzykowski (2004).

The design fire curve described above addressed only a single

cubicle burning. Prior to fire department intervention, the fire

spread to more than one cubicle in all scenarios. The

experimental data were used to determine a critical ignition

criterion for nearby cubicles. Once the fire spreads to nearby

cubicles, the HRR is simply additive. For additional information

on the design fire development, see Appendix G.

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Presently, fire suppression is not directly calculated within FDS.

In order to simulate a fire in which suppression is applied by

firefighters, the design fire curves were modified to represent the

timing and outcome of suppression. An exponential decay was

used to ramp down the design fire HRR from its value at Water

on Fire time to 50 kW at Fire Out time and then to 0 kW two

seconds later.

One limitation of this approach is that the suppression time is

assumed to be independent of the HRR value at the time of water

on fire. Whether the HRR is 1 MW or 10 MW at the time of water

on fire, the magnitude of HRR will decay to 50 kW at the Fire Out

time derived from the time­to­task exercises. A larger fire may

take longer to extinguish; however, an experimental basis for the

relationship between fire size and time to suppression does not

exist. Here, engineering judgment is used.

A second assumption is that two 2 1⁄2 inch hose lines will provide

sufficient water flow to extinguish the fire. In practice, some of the

design fires may be too large for the water supply, preventing

firefighters from reducing the HRR.

The source of data for the suppression algorithm is the

time­to­task data for the engine crews advancing the primary and

second hose lines on the fire floor. These times can be influenced

by the crew size and the method for ascending from the lobby to

Staging (stairs/elevators). Table 10 shows the average times for

Water on Fire and Fire Out for the replicates of each crew size and

ascent method, holding deployment (high/low) constant. The

rows in the table are sorted by time to water on fire, from longest

time to shortest.

The first takeaway from Table 10 is that, for each crew size,

firefighters would be able to get water on the fire and put the fire

out faster when taking the elevator to the staging area versus

taking the stairs. The second key point comes from examining the

impact of stairs versus elevators across crew sizes. Table 10 shows

that the average water on fire time for a 4­person crew using the

stairs is longer than the average water on fire time for a 3­person

crew using the elevator. The average 4­person crew taking the

elevator is also faster in getting water on the fire than the average

5­person crew and 6­person crew taking the stairs. The third

takeaway from the table is that the larger crews can make up the

Crew Size Ascent Method Average Water on

Fire Time (MM:SS) 

Average Fire Out

Time (MM:SS) 

3 Stairs 18:48 28:04 

4 Stairs 17:01 26:22 

3 Elevator 15:45 26:48 

5 Stairs 15:19 24:33 

6 Stairs 14:52 21:17 

4 Elevator 14:47 24:02 

5 Elevator 14:21 23:20 

6 Elevator 12:10 19:32 

gains associated with using the elevators instead of the stairs. The

6­person crew using the stairs has a faster average Fire Out time

compared to the 4­person and 5­person crews that had faster

water on fire times.

11.5 Ventilation

Ventilating through exterior windows is not commonly a tactic

in high­rise firefighting operations. This is due to the fact that

broken glass on an upper floor can injure people and damage

equipment (such as hose lines) on the ground below the windows,

as well as creating the potential for a wind­driven fire scenario.

Therefore, the only window breakage captured in the simulations

was due to thermal effects from the fire. The thermal breakage

model uses a critical temperature difference across the

windowpane as the basis for failure (Pagni and Joshi 1991). Exact

thermal properties of the glass installed in the high­rise were not

known, so assumptions were made based on typical pane glass.

Based on the thermal breakage model from Pagni using assumed

properties of the glass, the breakage criteria was set at a

temperature gradient of 100 °C. The temperature gradient was

measured by taking the difference between two point sources

located on the exposed and shielded areas of the windows,

respectively. If the breakage criterion was met, the entire window

was removed.

In an effort to keep the variations between simulations limited

to the three study variables, ventilation was held constant. The

order and timing of windows breaking was based on the

simulation of a 6­person crew that used the elevator to reach a

fast growth rate fire. This scenario represents both the largest fire

size and the crew size that gets water on the fire fastest. In total,

ten windows on the East side of the structure broke.

11.6 Fixed Fire Sprinkler Systems

A properly engineered and maintained fire sprinkler system can

be highly effective in limiting the size of an unwanted building

fire. Sprinkler systems are effective at protecting building

occupants, firefighters, and property. According to the NFPA, a

working sprinkler system is 96 % effective at controlling the

growth and spread of fires in structures (NFPA 2006). Due to a

number of high­profile fires in high­rise buildings

and considering their demonstrated effectiveness,

sprinkler systems are often required in new

high­rise buildings and many jurisdictions have

required existing high­rise buildings to be retrofit

with sprinkler systems.

However, sprinkler systems are not found in all

high­rise buildings. According to the NFPA (NFPA

2011), 41 % of high­rise office buildings are not

protected by sprinkler systems (compared to 25 %

of high­rise “care of sick” facilities, 45 % of

high­rise hotels and 54 % of high­rise apartment

buildings). Therefore, much of this report is

focused on analysis of fire department deployment

configurations responding to fires in an

unsprinklered high­rise building.

Table 10: Comparison of the impact of crew size and ascent method on average

firefighter suppression time

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erson3-P Stairs 6-P atorvEleerson6-P

 

 

 

Note, however, that sprinkler systems are designed to control

fires rather than to suppress them. Fire department response is

still required even in fully­sprinklered high­rises in order to

extinguish the fire, to search for and rescue occupants requiring

assistance, and to control the sprinklers (limiting water damage).

NFPA estimates that sprinkler systems fail to operate in 7 % of

structure fires (one of every fourteen fires) primarily due to

human error. A full two­thirds (65 %) of the sprinkler failures

were because the system had been shut off before the fire. Another

one­sixth (16 %) occurred because manual intervention defeated

the system, for example, by shutting off the sprinklers

prematurely. Lack of maintenance accounted for 11 % of the

sprinkler failures and 5 % occurred because the wrong type of

system was present. Nearly all failures were therefore entirely or

primarily problems of human action. Only 3 % involved damage

to system components.” (NFPA 2006) Therefore, even when a

large proportion of high­rise buildings within a jurisdiction are

protected by sprinkler systems, the fire department should be

prepared to deploy resources to hazards consistent with

unsprinklered fires.

The computer fire modeling simulations assuming a sprinkler

system were conducted with a specified typical sprinkler array

located above the cubicle in which the fire starts. The sprinkler

locations and activation properties used in the simulations were

based on conventional response sprinklers and typical sprinkler

locations. The sprinklers were set to activate when the

surrounding gas temperature reached 74 °C.

For these simulations, sprinklers were assumed to be able to

contain but not extinguish the fire. Containment was achieved in

the model by fixing the HRR value from the time of sprinkler

activation until the time when firefighter suppressive actions

caused the HRR to decay. The slow, medium, and fast fires have

unique sprinkler activation times and therefore have unique

plateau/peak values of HRR.

The impact of the sprinklers is seen in Table 11, where the peak

HRR value for the fast fire of approximately 1.7 MW is less than

the peak of a single cubicle fire of approximately 2.5 MW (as

shown in Figure 90).

Note that since the HRR in simulations with sprinklers is less

than in the non­sprinklered cases, the ventilation must be

t

2

 Fire Growth 

Rate 

Sprinkler Activation

Time (MM:SS) 

Peak HRR 

Value (MW) 

Slow 4:54 0.41 

Medium 2:45 0.64 

Fast 2:15 1.69 

Table 11: Sprinkler activation time and peak HRR value for slow,

medium, and fast growth rate fires

recalculated.Ventilation in the sprinkler simulations followed the

same procedure and criteria as in the non­sprinklered cases. By

the time sprinklers activate, a total of two windows have broken.

Given a properly engineered and functioning sprinkler system,

computer fire modeling results in this report reveal significantly

lower temperatures, toxic species concentrations, and smoke

obscuration when the sprinkler system is able to control fire growth

and spread. As a result, when the sprinkler system operates, these

results confirm that the total risk to occupants and firefighters is

greatly lessened across all deployment configurations.

11.7 Fire Modeling Results

Effects on Fire Development

The time advantages gained by larger engine crew sizes and/or

by using elevators impacted the interior conditions on the fire

floor (i.e., temperature, visibility, toxicity, etc.). For medium

growth rate fires, entering firefighters encountered fires between 5

MW to 11 MW in size, depending on crew configuration and

ascent method. This range in fire size can be visualized as the

equivalent of two cubicles on fire for a 6­person crew versus five

cubicles on fire for a 3­person crew, as demonstrated in Figure 91.

For a fast fire, the fire size in terms of cubicles on fire increased

from two for 6­person crews to eight for 3­person crews (13 MW

to 20 MW). For a slow growth fire, all crew sizes got water on the

fire before the fire grew past two cubicles (2.5 MW to 5 MW).

Due to the length of time for which these fires burn (between 12

min and 28 min on average), the number of cubicles burning at

3-Person Stairs 6-Person Elevator

Figure 91: Visualization of HRR for a medium growth fire for a 3­person crew using the stairs (left) and a 6­person crew using

the elevators (right) at the time firefighters make entry to the floor

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any given time can vary. Depending on the growth rate, some

cubicles may be in the growth phase, some in the steady burning

phase, and some in the decay phase.As a result, the instantaneous

HRR value may be higher at an earlier time, even though the

conditions on the fire floor may be worse as more total heat has

been released. Consider the HRR curves for a slow, medium, and

fast growth fire for a 6­person crew using the elevators in Figure 92.

Focusing on the fast growth rate fire (top curve), the HRR

reaches a steady rate of approximately 5 MW (two cubicles) at

0 6 12 18 24 30 

0 

2 

4 

6 

8 

10 

12 

14 

16 

18 

20 

Time (min) 

Heat Release Rate (MW) 

Slow 

Medium 

Fast 

Water On Fire 

Figure 92: HRR curves for the three growth fires for a 6­person crew

taking the elevator. The vertical line represents the Water on Fire

time and the start of firefighter suppression

about 3 min. There is steady burning at 5 MW until the fire ramps

up to 15 MW shortly after 6 min. The steep ramp indicates that

the fire has spread from the two original cubicles to four

additional cubicles. From the peak value of 15 MW, the HRR

decays to approximately 13 MW at 12 min. This decay occurs

because the initial two cubicles are in the decay portion of the

HRR curve, as shown by the experimental cubicle fire plotted in

Figure 90.

The area under the curve in Figure 92 represents the total

amount of heat released. Moving left to right on the plot

represents an increase in total heat release even if the

instantaneous value of HRR might be decreasing. Additionally,

the fuel load in the high­rise is sufficient such that burning will

continue without intervention. Therefore, prior to suppression, it

is more informative to consider the total heat release at the time

of water on fire than the instantaneous values.

Table 12 shows the total heat released by the fire from the time

of ignition until suppression actions begin, as a function of crew

size, ascent method, and fire growth rate. The units of the values

are GJ, where a joule is a standard measure of energy.

The values shown in Table 12 are sorted by the amount of heat

released at the time of entry to the fire floor, which illustrates the

impact of getting to the fire faster. Moving up and down a column

of this table shows the impact of crew configuration and ascent

method on total heat release. Moving left to right shows the

impact of varying the fire growth rate holding configuration and

ascent method constant. Referring back to Table 10, a 6­person

crew taking the elevator gets water on the fire 6 min 38 s faster

than a 3­person crew taking the stairs. This time difference results

in the 3­person crew facing interior conditions with total heat

release from 2 to 3 times greater than that faced by the 6­person

crew, depending on the fire growth rate.

Crew Size Ascent Method 

Total Heat Release by Fire Growth Rate (GJ) 

Slow Medium Fast 

3 Stairs 3.0 7.1 13.7 

4 Stairs 2.4 5.9 11.7 

5 Stairs 1.9 4.7 9.9 

6 Stairs 1.8 4.4 9.4 

3 Elevator 2.1 5.2 10.8 

4 Elevator 1.7 4.2 9.0 

5 Elevator 1.6 4.0 8.8 

6 Elevator 1.0 3.0 6.6 

Table 12: Comparison of the impact of crew size and ascent method on total heat release prior to

suppression actions

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Tenability Results for CO, O2, CO2

On the fire floor, the victim was located in the cubicle

containing button 18. The local fractional effective dose (FED) of

toxic gases experienced by the victim during these hypothetical

fires can be calculated based on the average time at which button

18 was pressed during experiments. In order to study the effects of

crew size and ascent method, data from high and low

deployments were combined. FED values at the time and location

of victim rescue for the three fire growth rates are shown in Table

13 as a function of crew size and ascent method.

In a slow growth rate fire, all crew configurations and ascents

could get to the victim before the lowest tenability threshold was

reached. As the fire growth rate increased to medium or fast, the

tenability was worse. In a medium growth rate fire, FED values for

the victim were above 1.0 (50 % threshold for incapacitation) in

the case of 3­person crews using the stairs only. In a fast­growing

fire, however, FED was above 1.0 for all firefighter configurations

except 6­person crews using the elevator. In this case, 3­person

crews using either ascent method failed to reach the victim until

the FED was greater than 3.0, for which the likelihood for

incapacitation is greater than 89 %.

The time­to­task experiments used a pre­determined, fixed

victim location in order to ensure repeatability and to evaluate the

impact of the three main study variables. In reality, a victim can

be located in any of the cubicles. It is therefore important to know

how FED evolves throughout the entire fire floor as a function of

time.

Ascent and 

Crew Size 

Victim Rescue 

Time (MM:SS) 

FED 

Slow Medium Fast 

3S 51:34 0.26 1.22 4.29 

4S 37:44 0.15 0.68 2.92 

5S 25:09 0.06 0.29 1.62 

6S 22:23 0.05 0.21 1.25 

3E 48:55 0.20 0.78 3.36 

4E 35:50 0.15 0.48 2.36 

5E 24:12 0.06 0.27 1.54 

6E 20:30 0.03 0.14 0.68 

Table 13: FED at the time of victim rescue on the fire floor as a function of crew size, ascent method,

and fire growth rate. See Table 8 for discussion of colors.

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0.0

0.3

1.0

3.0

3-Person Stairs

5-Person Stairs

4-Person Stairs

6-Person Stairs

Figure 93: FED contours at an elevation of 3 ft (0.9 m) on the fire floor for a medium growth non­sprinklered

fire at the time of firefighter entry

0.0

0.3

1.0

3.0

3-Person Stairs

5-Person Stairs

4-Person Stairs

6-Person Stairs

Figure 94: FED contours at an elevation of 3 ft (0.9 m) on the fire floor for a medium growth non­sprinklered

fire at the time the search is complete

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Figure 93 shows FED contours at an elevation of 3 ft (0.9 m) on

the fire floor at the time of firefighter entry on the floor for each

crew size taking the stairs, assuming a medium growth rate fire.

(Recall from Figure 90 that the experimental cubicle fire data best

follows a medium growth rate.) When firefighters in the 3­person

crew entered the fire floor, FED values in the cubicles along the

south wall were between 0.3 and 1.0.Values in this range impact

between 11 % and 50 % of the population. For the larger crew sizes,

the majority of the floor area remained below FED values of 0.3.

Figure 94 compares the FED values on the fire floor under the

same experimental conditions at the time the search is completed.

As expected, the hazard at this time decreases as crew size

increases. For both 3­person and 4­person crews, a significant

area on the fire floor is above an FED of 1.0. The 5­person and

6­person crews encounter FED levels above 0.3, but no regions

rise above an FED of 1.0.

To better quantify the FED on the fire floor, the percentage of

floor area in each FED band is examined. The stacked bar charts

in Figure 95 show area percentages from the highest FED range to

the lowest for crews using the stairs, summing to 100 %. The

charts allow comparison of different crew sizes on tenability of

the entire floor at three critical times unique to each test

configuration. By the time a 3­person crew has completed the

search for victims, approximately 45 % of the floor area has an

FED greater than 1.0 and less than 3.0. This can be compared to a

search completed by a 6­person crew, at which time the FED for

45 % of the floor area is greater than 0.3 but less than 1.0.

Entry Victim Rescue Search Complete 0 

10 

20 

30 

40 

50 

60 

70 

80 

90 

100 

Percentage Floor Area (%) 

FED ≥ 3.0 

1.0 ≤ FED < 3.0 

0.3 ≤ FED < 1.0 

FED < 0.3 

3-Person Stairs

Entry Victim Rescue Search Complete 0 

10 

20 

30 

40 

50 

60 

70 

80 

90 

100 

Percentage Floor Area (%) 

FED ≥ 3.0 

1.0 ≤ FED < 3.0 

0.3 ≤ FED < 1.0 

FED < 0.3 

5-Person Stairs

Entry Victim Rescue Search Complete 0 

10 

20 

30 

40 

50 

60 

70 

80 

90 

100 

Percentage Floor Area (%) 

FED ≥ 3.0 

1.0 ≤ FED < 3.0 

0.3 ≤ FED < 1.0 

FED < 0.3 

4-Person Stairs

Entry Victim Rescue Search Complete 0 

10 

20 

30 

40 

50 

60 

70 

80 

90 

100 

Percentage Floor Area (%) 

FED ≥ 3.0 

1.0 ≤ FED < 3.0 

0.3 ≤ FED < 1.0 

FED < 0.3 

6-Person Stairs

Figure 95: FED area percentages of the fire floor at an altitude of 3 ft (0.9 m) at times of entry, victim rescue,

and search complete for a non­sprinklered medium growth fire. See Table 8 for discussion of colors.

91
                   

                     

                     

                 

             

                     

           

                         

                         

                    

               

 

 

 

Victims may be situated anywhere on the fire floor. Therefore, in experimental configuration. Figure 96 through Figure 103 show

order to generalize the determination of FED at the time of rescue the FED values on the fire floor at the time of the average button

to victims in places other than the cubicle marked by button 18, press as a function of crew size and means of ascent for a medium

the non­uniform contours of FED on the fire floor can be growth rate fire. These figures show the ascent by stairs and

combined with the experimental time­to­task data by calculating elevator in each of the crew sizes studied.

FED values at the time and location of button press for each

Figure 96: FED at button press — Crew size of 3 using stairs Figure 97: FED at button press — Crew size of 3 using elevator

Figure 98: FED at button press — Crew size of 4 using stairs Figure 99: FED at button press — Crew size of 4 using elevator

Figure 100: FED at button press — Crew size of 5 using stairs Figure 101: FED at button press — Crew size of 5 using elevator

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Figure 102: FED at button press — Crew size of 6 using stairs

The treatment of buttons located near the fire in Figure 96

through Figure 103 should be interpreted with caution. Note that

button 22 is not included in these figures. Due to the location of

button 22 relative to the fire location and ventilation through the

windows, the FED value remains near ambient while the thermal

conditions are not survivable. As a result, presenting FED

information on this button location would be misleading with

respect to the rest of the fire floor and the variables of study in

this experiment. A similar argument could be made for buttons 21

and 23 due to their proximity to the windows and fire. However,

the large interior columns between these buttons and the fire

Button 

Number 

FED by Crew Ascent and Size 

3S 4S 5S 6S 3E 4E 5E 6E 

1 0.46 0.28 0.19 0.15 0.21 0.16 0.14 0.10 

2 0.43 0.26 0.18 0.14 0.20 0.15 0.13 0.09 

3 0.55 0.43 0.26 0.19 0.29 0.20 0.19 0.14 

4 0.64 0.42 0.26 0.19 0.28 0.20 0.19 0.15 

5 0.65 0.43 0.27 0.19 0.37 0.21 0.20 0.15 

6 0.66 0.51 0.32 0.20 0.39 0.21 0.22 0.17 

7 0.56 0.40 0.27 0.14 0.31 0.19 0.16 0.12 

8 0.50 0.28 0.21 0.11 0.27 0.15 0.12 0.11 

9 0.47 0.31 0.22 0.16 0.27 0.16 0.14 0.12 

10 0.39 0.23 0.08 0.07 0.23 0.14 0.09 0.05 

11 1.14 0.86 0.27 0.16 0.82 0.49 0.19 0.11 

12 1.59 0.93 0.36 0.23 0.96 0.55 0.29 0.15 

13 1.59 0.87 0.33 0.22 0.93 0.52 0.28 0.15 

14 1.48 0.79 0.28 0.18 0.88 0.48 0.22 0.13 

15 1.32 0.71 0.28 0.19 0.84 0.45 0.25 0.14 

16 1.52 0.84 0.30 0.20 0.93 0.52 0.27 0.14 

17 1.29 0.67 0.30 0.18 0.83 0.45 0.24 0.13 

18 1.22 0.68 0.28 0.21 0.78 0.48 0.27 0.14 

19 1.29 0.88 0.43 0.28 0.85 0.53 0.37 0.19 

20 0.71 0.44 0.20 0.15 0.47 0.29 0.17 0.11 

21 0.18 0.14 0.09 0.06 0.14 0.11 0.08 0.05 

23 0.71 0.51 0.31 0.19 0.49 0.30 0.23 0.12 

24 0.63 0.42 0.26 0.18 0.39 0.28 0.21 0.12 

Figure 103: FED at button press — Crew size of 6 using elevator

minimize thermal effects. For completeness these buttons are

included in the tenability analysis, although it must be noted that

the thermal component should be considered.

The survivability advantage provided by firefighter ascent using

elevators rather than stairs is demonstrated by comparing each

figure in the right column above to the figure for the same crew

size in the left column. Scanning down each column of figures

shows that for a given ascent method, a larger crew reaches

potential victims when the FED is lower. To better quantify the

impact, Table 14 shows the FED values that correspond to each of

the data points in Figure 96 through Figure 103.

Table 14: FED at the

time of button press on

the fire floor, as a

function of crew size

and ascent method for

a medium growth rate

fire without sprinklers

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Table 14 shows the impact of crew size and ascent method on

FED at each of the point locations (buttons) where there was a

time history of firefighter position. The highest FED values,

indicating greater tenability hazards, are typically related to the

smaller crew sizes. There are some outliers, specifically when

examining 3­person elevators versus 4­person stairs. The 3­person

crews show lower FED values than the 4­person crews on the

inner loop buttons (1­9) because the search advantage of a

4­person crew does not show up until the second crew arrives and

can split. These differences are also seen on the inner loop buttons

for a 5­person crew using the stairs versus a 4­person crew using

the elevators. However, as the search proceeds in time, the

5­person crew can reach the outer loop buttons at lower FED

values than the 4­person crew. Both 6­person crews can search the

entire floor without having any of the potential victim locations

exceed an FED value of 0.3, which is the lowest FED threshold.

Also note that FED values at button 21 remain below the lowest

threshold despite being among the last buttons to be pressed. As

discussed previously, this is because the button is located near the

windows that break due to thermal failure.Ventilation allows for

toxic gases to exit the structure; however, the low FED values do

not mean that this area is tenable.

Button 

Number 

FED by Crew Ascent and Size 

3S 4S 5S 6S 3E 4E 5E 6E 

1 0.04 0.03 0.03 0.03 0.03 0.03 0.01 0.02 

2 0.04 0.03 0.03 0.02 0.03 0.02 0.01 0.02 

3 0.05 0.04 0.03 0.03 0.03 0.03 0.01 0.03 

4 0.05 0.04 0.03 0.03 0.03 0.03 0.01 0.03 

5 0.06 0.05 0.04 0.03 0.04 0.03 0.01 0.03 

6 0.06 0.06 0.04 0.03 0.05 0.03 0.01 0.04 

7 0.06 0.05 0.04 0.03 0.04 0.04 0.01 0.03 

8 0.08 0.05 0.05 0.03 0.05 0.04 0.01 0.04 

9 0.07 0.06 0.05 0.04 0.05 0.04 0.01 0.03 

10 0.06 0.04 0.02 0.01 0.05 0.03 0.01 0.01 

11 0.09 0.08 0.03 0.02 0.10 0.06 0.01 0.02 

12 0.14 0.09 0.04 0.03 0.13 0.07 0.02 0.03 

13 0.15 0.09 0.04 0.03 0.13 0.07 0.02 0.03 

14 0.15 0.09 0.03 0.03 0.13 0.07 0.02 0.02 

15 0.16 0.09 0.04 0.03 0.14 0.08 0.02 0.03 

16 0.16 0.09 0.04 0.03 0.13 0.07 0.02 0.03 

17 0.16 0.09 0.04 0.03 0.13 0.08 0.02 0.03 

18 0.17 0.10 0.04 0.04 0.14 0.09 0.02 0.03 

19 0.20 0.15 0.07 0.06 0.16 0.11 0.02 0.06 

20 0.16 0.12 0.06 0.05 0.14 0.10 0.02 0.05 

21 0.13 0.10 0.05 0.04 0.12 0.08 0.01 0.04 

23 0.12 0.09 0.06 0.04 0.10 0.08 0.00 0.04 

24 0.11 0.09 0.07 0.05 0.10 0.07 0.02 0.05 

Table 15: FED at 3 ft elevation at the time of each fire floor button press, as a function of crew

size and ascent method for a medium growth rate fire with sprinklers

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Sprinklers

The FED analysis above was conducted for a non­sprinklered

structure. To examine the impact of sprinklers on the tenability of

the fire floor, Table 15 lists the FED values at each button for each

crew configuration for a sprinklered medium growth fire. In this

case, the FED values remain well below the first threshold value of

0.3 for all crew sizes and ascent methods. Tenability is greatly

improved compared to the non­sprinklered fires, as is expected

for cases in which sprinklers limit the fire growth. Holding

everything else constant, smaller fires produce a lower amount of

toxic gases and thus decrease FED values.

11.8 Building Evacuation

The high­rise time­to­task experiments were conducted in a

building without occupants present. Depending on the time of

day, a typical commercial high­rise may have hundreds or

thousands of occupants. A complete evacuation of occupants

could require significant time. This is important for the

time­to­task experiments because during this evacuation time

period the occupants may interact in an unknown way with the

arriving firefighters, particularly in the stairs. If evacuation is not

complete prior to firefighter arrival, the presence of evacuees in

stairwells will impede the progress of ascending firefighters. This

would result in longer ascent times than those measured in the

experiments. Therefore, the times determined in the experiments

are considered a conservative (best­case) scenario.

The length of overlap time when occupants are exiting and

firefighters are entering is important for understanding the degree

to which the experimental times may be delayed (i.e., how many

of the arriving crews are impacted). To determine a reference time

for expected complete evacuation, the NIST Egress Estimator

model was used (Reneke et al., 2013). The Egress Estimator uses

separate calculations to estimate the egress times for stairwell

evacuation and elevator evacuation; both have been validated

against data from experiments similar to the high­rise scenario

evaluated in this report. The stairwell model is based on

algorithms from the SFPE Handbook (Nelson and Mowrer, 2002)

and the elevator model is based on the ELVAC model (Klote,

1993). The maximum time between the model results is taken to

determine a conservative overall building evacuation time.

For egress analysis of the high­rise building used for these

experiments, two occupant loads were used: 100 occupants per

floor and 200 occupants per floor. The 100 occupants­per­floor

load was determined based on the open­floor plan cubicle

construction that was completed for the fire floor (counting the

number of desks). The 200 occupants­per­floor load was based on

a recommendation from Muha that a general office space should

have a load of 1 person per 150 sq ft (19.9 m2

) (Muha, 2012). For

the 30,000 square foot (2800 m2) floor plan, this loading results in

200 occupants per floor. Using the Egress Estimator model, the

total evacuation time was calculated for the two occupant loads

and two egress criteria. The first criterion was that all of the

occupants would exit the high­rise via one of the two available

stairwells. The second criterion was that 25 % of the occupants on

each floor would use two of the four elevators while the

remaining 75 % of the occupants would use the stairs. Two of the

elevators were reserved for firefighter use. Table 16 shows the time

for total evacuation for the two occupant loads and two

evacuation configurations.

In these experiments, firefighters enter the lobby 7 min 4 s after

first detection and the start of evacuation. This time includes 60 s

for alarm processing (NFPA 2010), 80 s for turnout time (NFPA

2010), and 4 min 44 s for travel time, unloading gear, and walking

to the lobby. For full occupancy at the 100 occupant per floor

loading, there can be approximately 5 min to 8 min where

ascending firefighters may face counter­flow conditions from

evacuating occupants. For the higher loading density the amount

of counter­flow can increase to between 15 min and 22 min.

Depending on the duration of counter­flow, ascending firefighters

using the stairs may be slowed. Therefore, the experiments that

compare the impact of stairs versus elevators are a best­case

comparison, as actual time differences may be more significant.

Average Occupant 

Load per Floor 

Evacuation 

Configuration 

Evacuation Time 

(MM:SS) 

100 Stairs Only 15:10 

100 Stairs + 25 % Elevators 12:28 

200 Stairs Only 29:28 

200 Stairs + 25 % Elevators 22:19 

Table 16: Total evacuation time as a function of occupant load and evacuation

configuration

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12. Physiological Effects on Firefighters
 

Reports on firefighter fatalities consistently document

overexertion/overstrain as the leading cause of line­of­duty

fatalities (NIOSH, 2013). There is strong epidemiological

evidence that heavy physical exertion can trigger sudden cardiac

events (Mittleman et al, 1993; Albert et al, 2000). Therefore,

information about the effect of crew size and vertical response

mode on physiological strain is very valuable.

During the planning of the high­rise fireground experiments, as

with the Residential Fireground Field Experiments, investigators

at Skidmore College recognized an opportunity to conduct an

independent study on the relationship between firefighter

deployment configurations, vertical response mode and firefighter

heart rates.

Investigators were able to leverage the resources of the high­rise

field experiments to conduct a separate analysis of the cardiac

strain on firefighters in the high hazard environment.

The results of this study are compiled in a separate report.

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13. Study Limitations
 

The scope of this study is limited to understanding the

relative influence of deployment variables to a working

high­rise structure fire. The applicability of the conclusions

from this report to low hazard residential, outside fires, natural

disaster response, HAZMAT or other technical responses has not

been assessed and should not be extrapolated from this report.

Fire Out times were determined by the time at which engine

crews moved the nozzle of the second line on the fire floor to the

origin of the fire. As the experiments could not utilize live fires,

the effect of fire size on suppression time was not captured. The

fire modeling results indicated that smaller crew sizes would face a

larger fire; for example a 3­person crew would face a fire of 11

MW, while the 6­person crew would face a fire of 5 MW.

Therefore, the time to fully suppress the fire (and the total toxic

dose received by trapped occupants) is likely underestimated by

an unknown amount in these experiments.

The total number of apparatus responding for each high­rise

experiment was held constant at 9 engines, 9 trucks, 3

ambulances, and 3 battalion chiefs for all crew size configurations.

The apparatus were dispatched in the high/low alarm groupings

as described in the report in Table 5. The effect of deploying more

or fewer than this total number of apparatus was not evaluated.

Fireground operations in these experiments were conducted

under best­case scenario conditions without many of the

complications that can occur in real fireground environments.

These complications can include, but are not limited to inclement

weather, nighttime operation, building security infrastructure that

may impede building access, elevator operation failure,

communications failures (both technological and interpersonal),

or power / fire technology failures.

Since the field experiments were conducted in a vacant building,

the counter flow effects of evacuating occupants on firefighter

ascent were not measured. Therefore, the recorded stairwell

ascent times are likely underestimated.

Fire crews participating in the experiments were provided by 13

different fire and rescue departments, each with their own

protocols, fireground tactics, training regimes, and equipment.

Standardized protocols were developed and implemented for the

high­rise experiments. Though similar, the protocols differed

from those used by the participating departments. Daily

orientation and crew cue cards were used to minimize the effects

of protocol differences. Since there is more than one effective way

to perform many of the required tasks on the high­rise

fireground, attempts to generalize the results from these

experiments to individual departments must take into account

tactics and equipment that vary from those used in the

experiments.

The fire crews that participated in the experiments typically

operate using 3­person and 4­person staffing. Therefore, the

effectiveness of the 5­person and 6­person operations may have

been influenced by a lack of experience in operating at those

staffing levels. Standardizing and assigning tasks likely minimized

the impact of this factor, although the actual influence on the

results is unknown.

Although efforts were made to minimize the effect of learning

across experiments, some participants took part in more than one

experiment, while others did not.

Though actual fire could not be used during the experiments, all

operations were handled according to NFPA 1403 and every

attempt was made to ensure the highest possible degree of

realism. Realistic digital fire displays and simulated smoke were

used on the fire floor and the floor above the fire. The quality of

simulated smoke was exceptional in replicating visual obscuration

for both fire attack and search and rescue operations. Digital fire

displays were also exceptional in visual simulation of live fire,

although thermal effects were lacking. Firefighters were informed

of all simulations and were asked to work and move as if they

were in a real fire environment. Though the instruction likely

minimized the effect, there was no ability to measure the actual

impact the use of simulation had on the results.

Though there was smoke breech to the floor above the fire, fire

spread beyond the floor of origin was not considered in the tests

or the fire models. Therefore, the size of the fire and the risk to the

firefighter may be somewhat underestimated for fast growing fires

or slower response configurations.

The scale and magnitude of the high­rise building was fixed. Fire

department response to ultra­high­rise buildings (e.g., buildings

greater than 420 ft (128 m) in height) may require customized

planning and resource allocation.

Radio communications throughout the experiments were

facilitated through two dedicated frequencies and interoperable

portable radios assigned to all crews. Typically, a high­rise

response, as for other structural fires, uses at least two radio

frequencies on the fireground—one for command and one for

tactical communication. Since one of the channels provided for

the experiments was used by researchers to communicate during

the experiments, only one channel remained for use in both

command and tactical communication. Even though both fire

officers and incident commanders were asked to minimize radio

communications to include protocol and critical needs only, the

simultaneous operations on multiple floors often caused delay in

officers’ communication with division supervisors and command.

The influence of limited radio communication was not evaluated.

The National Incident Management System (NIMS) was used

throughout the experiments. It was assumed that chief officers

assigned to the experiments know and frequently use the system

in actual operations. Therefore, there was no training or

orientation to the NIMS during the experiments. In an effort to

control variance in technique from chief to chief, each IC was

given a specific protocol to follow for crew assignments and was

advised to hand off the operations sections in the two most

hazardous areas (on the fire floor and floor above the fire) early in

the incident, so that other priorities could be addressed.

Due to the magnitude of the experiments, fireground operations

record keeping was essential. To limit variance in record keeping,

each IC had an assigned aide who recorded situation reports,

resource status and company assignments. Units operating on the

fire floor and the floor above the fire were managed by operations

section chiefs, who documented which companies were active on

their assigned floor. Effective operation of the Chiefs assigned to

these positions was dependent on their understanding and

experience with the NIMS and was not measured.

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14. Conclusions
 

Overall, the results of this study show that the number of

fire service crew members in each company responding to

a fire in a 30,000 square foot, thirteen­story structure had

a dramatic effect on the crew’s ability to protect lives and

property. Three significant conclusions are discussed below.

First, when responding to a medium growth rate fire on the

10th floor, 3­person crews ascending to the fire floor confronted

an environment where the fire had released 60% more heat

energy than the fire encountered by the 6­person crews.

Unfortunately, larger fires expose firefighters to greater risks and

are more challenging to suppress.

Second, larger fires produce more risk exposure for building

occupants. In general, occupants being rescued by smaller crew sizes

and by crews that used the stairs rather than the elevators were

exposed to significantly greater dose of toxins from the fire. While

the exact risk exposure for an occupant will depend on the fire

growth rate, their proximity to the fire, and the floor on which the

fire is located, it is clear that on­scene deployment decisions can have

a dramatic impact in determining the fate of building occupants.

Third, the study confirmed that a properly engineered and

operational fire sprinkler system drastically reduces the risk

exposure for both the building occupants and the firefighters.

While this has been well understood for many years and most new

high­rise buildings are constructed with fire sprinkler protection,

NFPA estimates that 41 percent of U.S. high­rise office buildings,

45 percent of high­rise hotels, and 54 percent of high­rise

apartment buildings are not equipped with sprinklers. Moreover,

sprinkler systems fail in about one in 14 fires. Thus, fire

departments should be prepared to manage the risks associated

with unsprinklered high­rise building fires.

Forty­eight laboratory and full­scale simulated fire experiments

were conducted to determine the impact of crew size, alarm size

and vertical response mode times on firefighter task completion

times responding to a high hazard high­rise commercial structure

fire. This report quantifies the effects of changes to staffing, alarm

size and/or vertical response mode for high hazard high­rise

commercial firefighting operations. While resource deployment is

addressed in the context of a high­rise structure type and

high­risk level, it is recognized that public policy decisions

regarding the cost­benefit of specific deployment decisions are a

function of many factors including geography, available resources,

community expectations, and local hazards and risks. Though this

report contributes significant knowledge to community and fire

service leaders in regard to effective resource deployment for fire

suppression, other factors contributing to policy decisions are not

addressed.

The objective of the experiments was to determine the relative

effects of crew size, alarm size, and vertical response mode on the

task completion times of the firefighting crews relative to

intervention times and the likelihood of occupant rescue. The

experimental results for each of these factors are discussed below.

Of the 38 high­rise fireground tasks measured during the

experiments, the following were determined to have especially

significant impact on the firefighting operations. Differential

outcomes based on variation of crew size, alarm size, and/or

vertical response mode times are discussed below.

Overall Scene Time

Overall scene time is the time that firefighters are actually engaged

in tasks on the scene of a structure fire and are unavailable for

dispatch to other incidents. The times noted do not include some

tasks such as salvage, overhaul and secondary search of the structure.

During the experiments, this time included typical operational tasks

with the exception of overhaul and salvage. The time to completion

of all tasks decreased as crew size increased. Three­person crews took

an average of about an hour to complete the fire response,whereas

crews of 6 firefighters required a mean time of just under 37 min for

completion. The performance of crews sized 4 and 5 were

in­between,with a crew size of 5 taking about 2 min longer than a

crew size of 6, and a crew size of 4 taking about 9 min longer than a

crew size of 5 but 12 min shorter than a crew size of 3. Therefore,All

Tasks Complete times were substantially reduced for crew sizes of 5

compared to 4, and 4 compared to 3.

Advance Attack Line

As firefighters engage on a fireground, putting water on the fire

is one of the most important tasks. Extinguishing the fire is

necessary to reduce the continuously escalating risks from fire

heat release and the toxic products of combustion. Before water

can be put on a fire however, a hose line must be stretched from

the standpipe in the stairwell to the compartment where the fire is

burning. Comparing each crew size to a 3­person crew, the time

differences increased with increasing crew size. From the

initiation of on­scene firefighting activities, a 3­person crew took

1 min 43 s (8.5 %) longer than a 4­person crew to stretch the

hose line. A 3­person crew took 2 min 47 s (13.9 %) longer than a

5­person crew to complete the same task. Finally, the most

notable difference was between a 3­person crew and a 6­person

crew, with a 4 min 28 s (22.3 %) task completion time difference.

Advance Second Line

The size of the fire in the experiments required two 2 1⁄2 inch

hose lines to fully suppress, therefore a second hose line had to be

advanced from the standpipe in the stairwell to the fire to assure

adequate water flow to extinguish. A 4­person crew took 2 min 43 s

(12.3 %) longer than a 5­person crew to complete the same task.

Finally, the most notable comparison was between a 4­person

crew and a 6­person crew, with a 5 min 38 s (24.1) difference in

task completion time.

Fire Out

Getting the fire out is critical to reducing risk to both firefighters

entering the structure and to trapped occupants. Based on fuel

available to burn, heat release accelerates and products of

combustion continue to poison the environment until the fire is

out. Fire Out, in the study, was defined as having both the attack

line and the second hose line in place. There was a 1 min 15 s (5.0

%) difference in the Fire Out time between the 4­ and 5­person

crews and a 3 min 29 s (12.7 %) difference between the 5­person

and 3­person crews). There was an additional 3 min 33 s (17 %)

difference in the Fire Out time between the 5­ and 6­person crews.

The 6­person crews extinguished the fire 7 min 2 s (25.6 %) faster

than 3­person crews.

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Search and Rescue 10th Floor

The fire floor in the experiments measured 30,000 sq ft (2800

m2) and contained 96 cubicles. Responding firefighters must

search every inch of the fire floor and adjacent stairwells to assure

that occupants have not been trapped, disabled or killed due to

the toxic environment or direct fire. In the high hazard high­rise

commercial building, the 4­person crews started the search and

rescue 1 min 23 s (7.8 %) earlier than the 3­person crews and

completed the search 11 min and 21 s (17.4 %) faster than the

3­person crews. In the same structure, the 5­person crews started

the search 1 min 4 s (6.7 %) earlier than the 4­person crews and 2

min 27 s (14.1 %) faster than the 3­person crews. Additionally,

5­person crews completed the search faster than the 4­ and

3­person crews by 13 min and 34 s (26.8 %) and 24 min 55 s (40.3

%) respectively. Six­person crews had the fastest performance,

starting the search 1 min 19 s (8.8 %) faster and completing the

search 2 min 57 s (8.0 %) faster than 5­person crews. The greatest

difference in search times was between 6­ and 3­person crews.

Six­person crews started the search on the fire floor 3 min 46 s

(21.7 %) faster and completed the search 27 min 51 s (45 %)

faster than the 3­person crews.

Victim #1 Found

There was a single victim located on the fire floor. The victim

was found and rescued by all crews. A 5­person crew operating in

the high­rise structure located the victim on the fire floor 25 min

18 s (50.6 %) faster than 3­person crews and 12 min 7 s (32.9 %)

faster than a 4­person crew. Likewise, 6­person crews located the

victim on the fire floor 28 min 33 s (57.1 %) faster than the

3­person crews, 15 min 21 s (41.7 %) faster than the 4­person

crew, and 3 min 14 s (13.2 %) faster than 5­person crews.

Victim #1 Rescue

Victim rescue requires at least two firefighters to carry a victim away

from the hazardous environment to safety and emergency medical

care. Removing a viable victim from the environment increases the

chance of survival. Five­person crews were able to remove the victim

from the fire environment 11 min 39 s (29.7 %) faster than the

4­person crews,while 6­person crews removed the victim from the

environment 14 min 58 s (38.1 %) faster than the 4­person crews and

3 min 19 s (12.0 %) faster than the 5­person crews.

Victim #1 Descent

Getting the victim out of the IDLH environment is not enough.

The victim must be removed from the building and when

necessary, transported to a hospital for examination and definitive

care.Five­person crews were able to facilitate victim descent 11

min 39 s (27.5 %) faster than 4­person crews and 24 min (43.1 %)

faster than 3­person crews, while 6­person crews were 3 min 19 s

(11.0 %) faster than 5­person crews.

Advance Line Above the Fire (11th Floor)

In a high­rise structure, it is essential to stretch a charged hose

line from the standpipe in the stairwell to the area above the fire

on the floor above the fire to extinguish fire that has spread

vertically from the floor of origin. A 3­person crew took 2 min 58 s

(11.5 %) longer than 5­person crews to complete the same task.

While the most notable comparison was between 3­person crews

and a 6­person crew, with a 3 min 37 s (14.0 %) difference in task

completion time.

Search and Rescue 11th Floor

The floor above the fire was separated into a number of

conference rooms and offices that had to be searched by each crew.

The area of the floor measured 30,000 sq ft (2800 m2

). Responding

firefighters must search every inch of the floor above the fire and

adjacent stairwells to determine whether occupants have been

trapped, disabled or killed due to the toxic environment. The area

of the floor measured 30,000 sq ft (2800m2). During the

experiments, the 4­person crews completed the search 9 min 31 s

(18.6 %) faster than the 3­person crews. Meanwhile, the 5­person

crews started a primary search/rescue 1 min 34 s (6.8 %) faster

than the 4­person crews and completed the search 2 min 37 s (6.3

%) faster than the 4­person crews. In the same structure, the

6­person crews also started the search 1 min 30 s (6.6 %) faster

than the 4­person crews but completed the search 5 min 8 s (12.3

%) faster than the 4­person crews.

Victim #2 Found

There was a single disabled victim located on the floor above the

fire. The victim was found and rescued by all crews. A 5­person

crew operating in the high­rise structure located the second victim

17 min 23 s (34 %) faster than a 3­person crew and 2 min 41 s (7.4

%) faster than a 4­person crew. Likewise, a 6­person crew located

the second victim on the floor above the fire 2 min 48 s (7.7 %)

faster than the 4­person crew.

Victim #2 Rescued

In addition to the victim on the fire floor, a second victim was

located on the floor above the fire. Each crew operating on this

floor was tasked with locating and rescuing the victim.Victim

rescue requires at least two firefighters to carry a victim away from

the hazardous environment to safety and emergency medical care.

Removing a viable victim from the environment increases the

chance of survival. Five­person crews were able to remove the

second victim from the fire environment 17 min 9 s (32.1 %)

faster than 3­person crews and 2 min 36 s (6.7 %) faster than the

4­person crews. Similarly, the 6­person crews rescued the victim 2

min 48 s (7.1 %) faster than 4­person crews.

Victim #2 Descent

Getting a victim out of the IDLH environment is not enough.

All victims must be removed from the building and when

necessary, transported to a hospital for examination and definitive

care. Six­person crews were able to facilitate victim descent 3 min

21 s (7.8 %) faster than 4­person crews. Additionally, victim

descent occurred nearly 6 min more quickly for crews using the

elevator rather than the stairs.

Summary of Regression Analysis

Crew Size

Generally, going from 3­person to 4­person crews significantly

reduced the time to begin advancing the attack line, to begin

advancing the second line, and to begin search and rescue. Task

begin­time reductions were in the range of 1 min 30 s. Going from

4­person to 5­person crews resulted in significant time reductions to

begin each critical task in the range of 1 min to 2 min. Increasing

crew size from 5­person to 6­person crews showed significant

reductions in begin time, just over 1 min, to advance the attack and

second lines and for search and rescue on the fire floor (10th floor).

When assessing task end times and incrementing crew size by a

single firefighter (i.e., 3 to 4, 4 to 5, and 5 to 6), the largest time

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improvements in time are seen when going from crew size 3 to 4.

As firefighter crews navigate the later tasks, the time improvements

reach the 10 min to 15 min range.Very large time improvements

are seen for the 10th Floor Search and Victim #1 Rescue tasks (over

11 min) when incrementing crew size from 4 to 5. The

improvements in All Tasks Complete end times are substantial (9.5

min to 12 min) when incrementing crew size from 3 to 4 or from 4

to 5.

Fire Service Access Elevators

All Tasks Complete occurred over 4 min more quickly when the

elevators were utilized compared to stairs. Begin times for nearly

every task above ground level and nearly all end times were

reduced compared to stair ascent. Most of the reductions due to

elevator usage were in the 2 min to 4 min range, with a few

obvious exceptions in that using fire service access elevators more

dramatically reduced times associated with upward and

downward transport of people or equipment. Using elevators to

transport air bottles and other equipment from the lobby to

Staging allowed completion of Establishment of Stairwell Support

over 10 min more quickly than moving the equipment manually

up the stairs. Additionally, the transport of both Victim #1 and

Victim #2 from Staging to the outside of the building was faster

when using the elevators (compared to the stairs), by 2 min 41 s

and 3 min 19 s, respectively. As a result, except for Establishment

of Stairwell Support and Victim Descent, there were no ascent

mode differences for task duration.

Alarm Size and Ascent Mode

About one third of the 27 distinct outcome­task comparisons

between high and low alarm size were statistically significant. Six

of the eight significant differences between high and low alarm

sizes involved reductions of task begin times ranging from 1 1⁄2

min to 2 1⁄2 min in favor of the high alarm size response. These

task begin times involved Primary Search of Floor 11,Victim #2

Rescue, and Advance Line Above Fire.

Combining Alarm Size and Crew Size

Given the findings from the crew size analysis that adding one or

two firefighters to a crew could generally achieve substantial task

time decreases, a logical question is whether the meaningful

benefits of a higher crew size could be realized by implementing a

higher alarm response at a smaller crew size (e.g., 4/high

compared to 5/low). The hypothesis might be that a high response

with lower crew size might yield similar results in task timing to

that of a low response with higher crew size.

Regression results shown in Appendix C3, comparing the effect

of a high response with lower crew size to a low response with

higher crew size showed that statistically significant differences

occurred for low alarm response with 4 or 5 crew size compared

to high response with crew sizes of 3 and 4, respectively. There

were significant reductions in begin times for all critical tasks

from Advance Attack Line through Victim #1 Rescue. Sizeable

reductions of about 12 min were also seen for Victim #2 Rescue.

These results suggest that a low alarm response with crews of size

4 or 5 outperforms a high alarm response with crew sizes smaller

by 1 firefighter. When decreases occurred, they were in the range

of 1 to just under 2 min. This pattern did not hold for low alarm

response with crew size 6 compared to high response with crew

size 5. The observed differences in times were significantly higher

for Search of Floor 11 and Advance Line Above Fire.

Combining Alarm Response and Ascent

In comparing different combinations of alarm response (high,

low) and ascent mode (stairs, elevator), results contrast several

combinations of alarm size and ascent mode.

Stairs/High vs. Stairs/Low — The alarm size had virtually no

effect for critical task timings, with the exception of Search of

the Floor Above the Fire (Floor 11) and Victim #2 Rescue. High

alarm size realized a mean reduction in the range of 1.5 min to

3.4 min for these tasks. The All Tasks Complete was also

significantly smaller for high alarm size by 3 min. No other task

timing comparisons were statistically different.

Elevator/High vs. Elevator/Low — In the elevator scenarios, high

alarm size led to eight significantly lower timings than did a low

alarm response. Results show a 45 s reduction in begin time for

Fire Out, Search of Fire Floor 10, and Victim #1 Found. Small

reductions of just over 1 min were noted in begin times for Search

Floor 11 and Victim #2 Found. Small reductions of 30 s to 2 min

were also noted for times related to Advance Line Above Fire. No

other task timing comparisons were statistically different.

Fire Modeling Results

In order to assess the hazard to occupants and firefighters as a

consequence of different deployment configurations, computer

fire modeling was performed. Three different ‘standard’ fires were

simulated using the NIST Fire Dynamics Simulator (FDS) model.

The three fires, characterized in the Handbook of the Society of

Fire Protection Engineers (Hadjisophocleous and Mehaffey 2008)

as slow, medium, and fast,33 grew exponentially with time and

had burning characteristics similar to the experimental results of

typical office cubicle fires (Madrzykowski et al. 2004)

Computer fire modeling demonstrated the effectiveness of a

working fire sprinkler system: the FED values remained well

below the threshold value of 0.3 regardless of crew size and ascent

method. Thus, the overall hazard is greatly improved compared to

the non­sprinklered fires for both firefighters and occupants.

According to the National Fire Protection Association, a working

sprinkler system is 96 % effective at controlling the growth and

spread of fires in structures (NFPA 2006). Due to a number of

high­profile fires in high­rise buildings and considering their

demonstrated effectiveness, sprinkler systems are often required

in new high­rise buildings and many jurisdictions have required

existing high­rise buildings to be retrofit with sprinkler systems.

However, sprinkler systems are not in all high­rise buildings.

According to the National Fire Protection Association (NFPA

2011), 41 % of high­rise office buildings are not protected by

sprinkler systems (compared to 25 % of high­rise “care of sick”

facilities, 45 % of high­rise hotels and 54 % of high­rise

apartment buildings). Therefore, much of this report is focused

on analysis of fire department deployment configurations

responding to fires in an unsprinklered high­rise building.

33.As defined in the SFPE Handbook, a fast fire grows exponentially to 1.0 MW in 2 min 30 s; a medium fire grows exponentially to 1 MW in 5 min; a slow fire grows exponentially

to 1 MW in 10 min.A 1 MW fire can be thought of as a typical upholstered chair burning at its peak.A large sofa may produce a fire with a peak HRR value of 2 MW to 3 MW.

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Sprinkler systems are designed to control, rather than suppress

fires. Fire department response is still required even in

fully­sprinklered high­rises in order to extinguish the fire, search

for and rescue occupants requiring assistance, and to control the

sprinklers (limiting water damage). NFPA estimates that

sprinkler systems fail to operate in 7 % of structure fires (one of

every fourteen fires) primarily due to human error. “Two­thirds

(65 %) of the sprinklers failed to operate because the system had

been shut off before the fire. Another one­sixth (16 %) failed

because manual intervention defeated the system, for example, by

shutting off the sprinklers prematurely. Lack of maintenance

accounted for 11 % of the sprinkler failures to operate and 5 %

occurred because the wrong type of system was present. Only 3

% of sprinkler failures involved damage to system components.”

(NFPA 2006)

Therefore, even if a large proportion of high­rise buildings in a

local jurisdiction are protected by sprinkler systems, a fire

department should be prepared to deploy resources to hazards

consistent with unsprinklered structure fires.

For unsprinklered scenarios, the time advantages gained by

larger engine crew sizes and by using elevators versus stairs

impacted the calculated interior conditions, including

temperature, visibility, and toxicity on the fire floor. For medium

growth rate fires, firefighters entering the environment would

encounter fires between 5 MW to 11 MW in size, depending on

crew configuration and ascent method. This range in fire size can

be approximately visualized as the equivalent of two cubicles on

fire for a 6­person crew versus five cubicles on fire for a 3­person

crew.

The calculations suggest that crew size and vertical ascent mode

can significantly affect the likelihood of a successful rescue of

victims on the fire floor. For victim rescue times discussed above,

FED34 values in the cubicle where the victim was located ranged

from 0.14 (6­person crew using the elevator) to 1.22 (3­person

crew using the stairs). An FED value of less than 0.3 indicates that

less than 11 % of the population would be incapacitated by the

toxic exposure, while an FED value of greater than 1.0 indicates

that greater than 50 % of the population would be incapacitated

by the specific toxic exposure. Consistently, smaller crew sizes

resulted in greater exposure to combustion products compared to

larger crew sizes. Additionally, using the stairs delayed rescue and

resulted in higher toxic exposure when compared to using the

elevators.

Evacuation Effects

The high­rise time­to­task experiments were conducted in a

vacant building. The only people present during the experiments

were active participants or observers. Depending on the time of

day, a typical commercial high­rise is not likely to be empty. A

complete evacuation of occupants could require significant time.

This is important for the time­to­task experiments, because

depending on the local fire code, evacuating occupants would use

the stairs and/or elevators. If evacuation is not complete prior to

firefighter arrival, the presence of evacuees in stairwells would

impede the progress of ascending firefighters. This would result in

longer ascent times than those measured in the experiments.

Therefore, these experiments are considered a best­case scenario.

Summary

The purpose of this report, in combination with the Residential

Fireground Report, is to provide fire chiefs and local

decision­makers with science­based relationships between

deployment variables (crew size, alarm size, and ascent mode) and

the resulting service outcomes, including risk to building occupants

and firefighters, as well as the potential for property loss.

The results of these field experiments contribute to the body of

knowledge about the fire service. First, the results establish a

technical basis for the consideration of company crew size, alarm

size and vertical response mode to NFPA 1710. The results also

provide valid measures of total effective response force assembly

on scene for high­rise fireground operations, as well as the

expected performance of time­to­critical­task measures for high

hazard high­rise commercial structure fires. Additionally, the

results provide tenability measures associated with occupant

exposure rates to the range of fires considered in this study

involving a large (20 MW) fire on the 10th floor of a high­rise. The

results of the project will also inform code provisions in Section

403 of the 2009 International Building Code which require fire

service access elevators in new construction over 120 ft (36.6 m).

34.To characterize the accumulated hazard associated with inhalation of gases typical of combustion products, a time­integrated value known as the fractional effective dose (FED)

is used. FED is an international standard, maintained by the International Standards Organization (ISO) and documented in ISO document 13571. FED is a probabilistic

quantity used to estimate the impact of toxic gases on humans(ISO 2007).). Forthis study, FED includes the impact of excess carbon monoxide and carbon dioxide inhalation

and oxygen depletion.

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15. Future Research
 

I

n order to realize improved firefighter safety and effectiveness,

resource allocation and the deployment of resources on fire

incidents of all hazard levels need consideration.

Future research should use similar methods for evaluating

firefighter resource deployment to extend the findings of this

report to quantify the effects of crew size and firefighter assembly

times on fires in medium hazard and other high hazard

structures, including multiple­family residences, schools,

hospitals, places of assembly, warehouses, mercantile

establishments consisting of a row of stores and restaurants, night

clubs, warehouse facilities, responses to large scale non­fire

incidents, or technical rescue operations.

Additionally, resource deployment to multiple­casualty disasters

should be studied to provide insight into levels of risks specific to

individual communities and to recommend resource deployment

proportionate to such risk. Future studies should continue to

investigate the effects of resource deployment on the safety of

both firefighters and the civilian population to better inform

public policy.

Investigating firefighter and civilian safety should also include

future research to assess counter­flow relationships between

firefighters entering and occupants exiting stairwells during

evacuation in a variety of structures.

Additional research is necessary to understand the economics of

improving fire resilience of structures within communities

including costs vs. benefit, total economic burden, role of fire

protection via fire service response, fire­resistant design, and/or

fire­resistant materials.

Future research is needed in the area of suppression effectiveness

based on the relationship between crew size and fire suppression

time for a range of different fires.

Future research opportunities should also consider EMS

response to multiple casualties in high­rise fires or other high

hazard occupancies.

Finally, research is needed in the area of radio communication

during a high hazard incident, when hundreds of firefighters are

at risk and communication is often profuse, interrupted,

misunderstood, garbled and/or chaotic. These issues extend

beyond the research currently underway in regard to radio

equipment and frequencies, which play a vital role in firefighter

safety on the fire ground.

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Acknowledgments
 

A project of this magnitude extends significantly beyond the

capabilities and expertise of the report authors. The following

groups and individuals were instrumental in the success of the

high­rise fireground field experiments.

n Subject Matter Experts — Russ Sanders, NFPA, Louisville KY

Chief Retired; Dennis Compton, IFSTA, NFFF, Mesa, AZ Chief

Retired; Peter Van Dorpe, Training Chief Chicago, IL; David

Rohr, Chief Fairfax City,VA/ Fairfax County,VA Operations

Chief, Retired; Vincent Dunn, Deputy Chief FDNY, Retired; Ben

Klaene, Cincinnati, OH Training Chief, Retired; James Walsh,

Deputy Chief, Fairfax County,VA; Richard Bowers, Chief

Montgomery County, MD; and Richard Travers, Deputy Chief,

FDNY, Retired.

n NIST Instrumentation Personnel — Michael Selepak, Artur

Chernovsky, and Scott Bareham.

n IAFF Staff and Interns — Data Entry/ Timers/Physiological

Monitors — Ron Benedict, Jamie Grimes, Mike Haertel, Joe

Bertoni, Alexa Sherman, and Devon Wolcott.

n IAFF Graphic Design — Kristin Hazlett

n Chief James Schwartz, Arlington County Fire and Rescue

Department for supporting this study to an unprecedented

degree.

n Vornado/Charles E. Smith, Washington Division Vornado

Realty Trust — Building Contact, Tanya Seyfert.

n Vornado/ Charles E. Smith, Washington Division Vornado

Realty Trust Building Engineers — Dave McCann, Mike

Fitzgerald, Nate Ford, Keith White, Carlton Carter (‘CC’).

n BullEx, Inc., digital fire and simulated smoke display equipment

— Ryan O’Donnell, President, John Blackburn, Inventor,
 

Simon Balint,VP of Sales.
 

http://www.bullexsafety.com/about.aspx
 

n Firefighting Crew Resources — David Rohr, Chief Fairfax City,

VA/Fairfax County,VA Operations Chief, Retired.

n Experiment Logistics and Monitoring — Richard Merrell,

Fairfax County Fire and Rescue Department.

n Building Construction and Props — Randy Carter, Chris

Hinkle, Chad McDonald, Joey Fuller III, Brady Miller, and

James Falise from Montgomery County Fire and Rescue

Department and Richard Merrell from Fairfax County Fire and

Rescue Department.

n Experiment Props, Radios and Apparatus Parking — Charles

Kramaric, Arlington County Fire and Rescue Department and

J.J. Walsh, Fairfax County Fire and Rescue Department.

n The Fire Chiefs and Operations Chiefs of the participating

departments along with the dedicated Fire Officers and

Firefighters who performed the difficult work of high­rise

structural firefighting safely and courageously.

• Arlington County Fire Department

• Alexandria Fire Department

• Fairfax County Fire and Rescue Department

• Prince William County Fire and Rescue Department

• District of Columbia Fire and EMS Department

• Montgomery County Fire and Rescue Services

• Howard County Department of Fire and Rescue Services

• Fairfax City Fire and Rescue Department

• Prince George’s County Fire/EMS Department

• Loudoun County Fire and Rescue Department

• Manassas City Fire and Rescue Department

• Stafford County Fire and Rescue Department

n Timers — dedicated fire officers and firefighters from Arlington

County Fire and Rescue Department, Fairfax County Fire and

Rescue Department, Fairfax City Fire and Rescue, Prince

George’s County Fire/EMS Department, and Alexandria Fire

Department assigned to the project for data collection.

n Metropolitan Washington Airports Authority — for the parking

area to stage several pieces of fire apparatus during the

experiments.

n Skidmore College — Denise Smith, Skidmore College and

Jeannie Haller, Skidmore College for supplemental

physiological study to bolster the significance of the main study

results.

n Zephyr — Ben Morris for physiological status monitoring

(PSM) high­rise operational environment.

n Finally, the study investigators wish to express our gratitude to

the public safety officials and the citizens of Arlington County,

Virginia for their support of the project.

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106
    

 

 

 

 

 

 

 

 

 

 

 

Appendix A: Data Collection and Company Protocols for Time-to-Task Tests

Time-to-Task Data Collection Chart – High-Rise Operations

(Chart colors denote tasks assigned to individual timers)

Task Start Stop 

Position Engine Wheels stopped, brake engaged (4:44) Chocks in place 

Connect to Standpipe Touch hose at engine to hook into 

Siamese 

Both hose lines connected to standpipe 

Siamese connection 

Test Hydrant Test hydrant - Water flowing from hydrant 

Connect to Hydrant Connection from pumper to hydrant 

complete 

Lines Charged (hydrant to pumper and 

pumper to Siamese) 

Both lines charged 

Initial Size-up 

(Check off each Task

as completed

First Dispatch (0:00) 

�Talk with building manager 

�Check alarm panel – locate fire and 

check status of building systems and 

HVAC 

�Access building keys 

�Locate fire control room 

Give command statement (time stamp) 

Establish Command First Dispatch (0:00) Officer crosses threshold, makes 

command statement (time stamp) 

Lobby Control First Dispatch (0:00) Key elevator for recall (check to assure 

they are all down) (time stamp) 

Verify status of elevators, pop panel from 

each and check with flashlight, and report 

whether or not elevators are functioning 

(time stamp) 

Attack and evacuation stairwells/elevators 

are located, designated, and confirmed 

(time stamp) 

Establish IRIC 2 crew members assembled on 8th floor, 

not on air, standing by and ready to assist 

in the event of firefighter emergency 

107
 

 

Establish RIT Crew enters stairwell/elevator from 

lobby 

Crew assembled on 8th floor landing 

Establish Medical, Rehab- Ambulance 1 Initial arrival, Ambulance 1 Crew enters staging with all equipment 

Establish Medical, Ambulance 2 Initial arrival, Ambulance 2 Crew enters staging with all equipment 

Establish Medical, Ambulance 3 Initial arrival, Ambulance 3 Crew enters staging with all equipment 

Establish Staging Initial arrival, Truck 3 Crew enters staging 

Establish Stairwell/Elevator Support Initial arrival, Truck 5 35 air cylinders, extra search rope, and 2 

coolers brought to staging 

Attack Crew Ascension Crew enters stairwell/elevator from 

lobby 

Crew assembled on 8th floor landing 

Attack Line-Connect To Standpipe Crew enters stairwell/elevator from 

lobby 

Attack line connected to gated wye valve 

Advance Attack Line Attack line nozzle through 10th floor 

stairwell door 

Attack line- Water on Fire 

Second Line Crew Ascension Crew enter stairwell/elevator from lobby Crew assembled on 8th floor landing 

Second Line-Connect to Standpipe Crew enters stairwell/elevator from 

lobby 

Second line connected to wye valve 

Advance Second Line Second line nozzle through 10th floor 

stairwell door 

Second line-Water on Fire 

Fire Out Attack line nozzle through 10th floor 

stairwell door 

Attack and second lines cross target 

threshold 

Check for Fire Extension on 10th Floor Firefighters touch pike pole Thirty pulls on weighted pike pole 

completed 

Positive Pressure Ventilation-Fans 1 min after Fire Out (time stamp) 

Roof Ventilation 1 min after Fire Out (time stamp) 

108
 

 

 

 

 

Search and Rescue Crew Ascension (Floor 

10) 

Crew enters stairwell/elevator from 

lobby 

Crew assembled on 8th floor landing 

Search and Rescue (Floor 10) Crew through 10th floor stairwell door Primary search on 10th floor completed 

Victim #1 Found (Floor 10) Crew through 10th floor stairwell door Victim found on 10th floor 

Victim #1 Rescue (Floor 10) Victim found on 10th

 floor Victim arrives on 8th floor landing 

Victim #1 Descent Victim exits 8th floor Victim exits building 

Line Above Fire Crew Ascension Crew enters stairwell/elevator from 

lobby 

All personnel assembled on 8th floor 

landing (stairwell) 

Line Above Fire-Connect to Standpipe Crew ascends from lobby Line above fire connected to wye valve 

Advance Line Above Fire Line above fire nozzle through 11th floor 

stairwell door 

Line above fire at target threshold 

Check for Fire Extension on 11th floor Firefighter(s) touch weighted pike pole Thirty pulls on pike pole completed 

Search and Rescue Crew Ascension (Floor 

11) 

Crew enter stairwell/elevator from lobby All personnel assembled on 8th floor 

landing (stairwell) 

Search and Rescue (Floor 11) Crew through 11th floor stairwell door Primary search on 11th floor completed 

Victim #2 Found (Floor 11) Crew through 11th floor stairwell door Victim found on 11th floor 

Victim #2 Rescue (Floor 11) Victim found on 11th floor Victim arrives on 8th floor landing 

Victim #2 Descent (Staging to Lobby) Victim exits 8th floor Victim exits building 

Search and Rescue (Upper Floor) Crew 

Ascension 

Crew enters stairwell/elevator from 

lobby 

Crew assembled on 8th floor landing 

Search and Rescue (Upper Floor) Crew through upper floor stairwell door Search completed (must have all 20 prop 

markers) 

Search and Rescue Crew Ascension (Floor 

9) 

Crew enters stairwell/elevator from 

lobby 

Crew assembled on 8th floor landing 

Search and Rescue (Floor 9) Crew through 9th floor stairwell door Search completed (must have all 20 prop 

markers) 

109
 

 

 

 

 

 

 

 

 

 

 

 

 

 

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 zz

 

 

Company          Protocols: Crew Size of 3
 

COMPANY TASK ASSIGNMENTS

Engine 1 Assume command

-Access building keys

-Locate fire control room

-Check alarm panel

-Give command statement

-Check status of elevators

-Designate attack and evacuation stairwells

Join Engine 2 to form attack crew

-Connect to gated wye valve on 9th floor

-Advance attack line to 10th floor

-Simulate water on fire

-Maintain sustained attack

Truck 1 Establish Initial Rapid Intervention Crew

Once Rapid Intervention Team is established, begin search and rescue on fire floor

-Check for extension, complete 30 reps on weighted pike pole

-Follow search pattern on floor, hit bu ers

-If victim is found, evacuate victim to 8th floor

Ambulance 1 Establish firefighter rehab on 8th floor

Engine 2 Join Engine 1 to join attack crew

-Connect to gated wye valve on 9th floor

-Advance attack line to 10th floor

-Simulate water on fire

-Maintain sustained attack

Ambulance 2 Report to 8th floor staging area

-Package and transport Victim #1

Engine 3 Establish back up line

-Connect to gated wye valve on 9th floor

-Advance back up line to 10th floor

-Simulate water on fire

-Maintain sustained attack

Truck 2 Establish Rapid Intervention Team on 8th floor

Ambulance 3 Report to 8th floor staging area

-Package and transport Victim #2

BC 1 Incident Command

Engine 4 Relieve attack line crew

Truck 3 Establish staging on 8th floor

Truck 4 Search and rescue, floor above fire

-Follow search pattern on floor, hit bu ers

-If victim is found, evacuate victim to 8th floor

BC 2 Division 10 Command

110
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Engine 5 Establish 3rd line to floor above the fire

-Connect to standpipe on 11th floor

-Advance 3rd line to compartment above the fire

-Check for extension, complete 30 reps on weighted pike pole

Ambulance 4 Report to staging

Engine 6 Lobby control

-Establish base outside of building

-Logistical support

-Check fire control room

Ambulance 5 Report to base

Engine 7 Relieve back up line crew

Ambulance 6 Report to base

Engine 8 Search and rescue upper floor (13th)

-Follow search pattern on floor

-Gather all 20 markers

Ambulance 7 Report to base

BC 3 Division 11 Command

Truck 5 Elevator/stairwell support

-Transport 35 air cylinders and 2 water coolers to staging

Ambulance 8 Report to base

Engine 9 Relieve 3rd line crew

Ambulance 9 Report to base

BC 4 Ventilation group supervisor

Engine 10 Report to staging, tactical reserve

Engine 11 Report to staging, tactical reserve

Engine 12 Report to base

Truck 6 Ventilation of attack stairwell

-Proceed to roof and burp hatch when "Fire Out" is heard

BC 5 Report to staging

Truck 7 Relieve search and rescue crew on fire floor

-If victim is found, evacuate victim to 8th floor

Truck 8 Search and rescue lower floor (9th)

-Follow search pattern on floor

-Gather all 20 markers

Truck 9 Relieve search and rescue crew on floor above fire

-If victim is found, evacuate victim to 8th floor

Truck 10 Report to staging, tactical reserve

BC 6 Report to staging, tactical reserve

Truck 11 Report to staging, tactical reserve

Truck 12 Report to base

111
 

 

 

 

 

 

 

 

 

 

 

 

 

 zz

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 zz

 

Company          Protocols: Crew Size of 4
 

COMPANY TASK ASSIGNMENTS

Engine 1 Assume command

-Access building keys

-Locate fire control room

-Check alarm panel

-Give command statement

-Check status of elevators

-Designate attack and evacuation stairwells

Join Engine 2 to form attack crew

-Connect to gated wye valve on 9th floor

-Advance attack line to 10th floor

-Simulate water on fire

-Maintain sustained attack

Truck 1 Search and rescue. 10th floor

-Check for extension, complete 30 reps on weighted pike pole

-Follow search pattern on floor, hit bu ers

-If victim is found, evacuate victim to 8th floor

Ambulance 1 Establish firefighter rehab on 8th floor

Engine 2 Establish Initial Rapid Intervention Crew

Once Rapid Intervention Team is established, join Engine 1 to form attack crew

-Connect to gated wye valve on 9th floor

-Advance attack line to 10th floor

-Simulate water on fire

-Maintain sustained attack

Ambulance 2 Report to 8th floor staging area

-Package and transport Victim #1

Engine 3 Establish back up line

-Connect to gated wye valve on 9th floor

-Advance back up line to 10th floor

-Simulate water on fire

-Maintain sustained attack

Truck 2 Establish Rapid Intervention Team on 8th floor

Ambulance 3 Report to 8th floor staging area

-Package and transport Victim #2

BC 1 Incident Command

Engine 4 Relieve attack line crew

Truck 3 Establish staging on 8th floor

Ventilation of attack stairwell

Truck 4

-Proceed to roof and burp hatch when "Fire Out" is heard

Search and rescue, floor above fire

-Follow search pattern on floor, hit bu ers

-If victim is found, evacuate victim to 8th floor

112
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BC 2 Division 10 Command

Engine 5 Establish 3rd line to floor above the fire

-Connect to standpipe on 11th floor

-Advance 3rd line to compartment above the fire

-Check for extension, complete 30 reps on weighted pike pole

Ambulance 4 Report to staging

Engine 6 Lobby control

-Establish base outside of building

-Logistical support

-Check fire control room

Ambulance 5 Report to base

Engine 7 Relieve back up line crew

Ambulance 6 Report to base

Engine 8 Search and rescue upper floor (13th)

-Follow search pattern on floor

-Gather all 20 markers

Ambulance 7 Report to base

BC 3 Division 11 Command

Truck 5 Elevator/stairwell support

-Transport 35 air cylinders and 2 water coolers to staging

Ambulance 8 Report to base

Engine 9 Relieve 3rd line crew

Ambulance 9 Report to base

BC 4 Ventilation group supervisor

Engine 10 Report to staging, tactical reserve

Engine 11 Report to staging, tactical reserve

Engine 12 Report to base

Truck 6 Relieve search and rescue crew on fire floor

-If victim is found, evacuate victim to 8th floor

BC 5 Report to staging

Truck 7 Search and rescue lower floor (9th)

-Follow search pattern on floor

-Gather all 20 markers

Truck 8 Relieve search and rescue crew on floor above fire

-If victim is found, evacuate victim to 8th floor

Truck 9 Report to staging, tactical reserve

Truck 10 Report to staging, tactical reserve

BC 6 Report to staging, tactical reserve

Truck 11 Report to base

Truck 12 Report to base

113
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 zz

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Company          Protocols: Crew Size of 5
 

COMPANY TASK ASSIGNMENTS

Engine 1 Assume command

-Access building keys

-Locate fire control room

-Check alarm panel

-Give command statement

-Check status of elevators

-Designate attack and evacuation stairwells

Join Engine 2 to form attack crew

-Connect to gated wye valve on 9th floor

-Advance attack line to 10th floor

-Simulate water on fire

-Maintain sustained attack

Truck 1 Establish Initial Rapid Intervention Crew

Once Rapid Intervention Team is established, begin search and rescue on fire floor

-Check for extension, complete 30 reps on weighted pike pole

-Follow search pattern on floor, hit bu ers

-If victim is found, evacuate victim to 8th floor

Ambulance 1 Establish firefighter rehab on 8th floor

Engine 2 Establish back up line

-Connect to gated wye valve on 9th floor

-Advance back up line to 10th floor

-Simulate water on fire

-Maintain sustained attack

Ambulance 2 Report to 8th floor staging area

-Package and transport Victim #1

Engine 3 Relieve attack line crew

Truck 2 Establish Rapid Intervention Team on 8th floor

Ambulance 3 Report to 8th floor staging area

-Package and transport Victim #2

BC 1 Incident Command

Engine 4 Establish 3rd line to floor above the fire

-Connect to standpipe on 11th floor

-Advance 3rd line to compartment above the fire

-Check for extension, complete 30 reps on weighted pike pole

Truck 3 Establish staging on 8th floor

Ventilation of attack stairwell

-Proceed to roof and burp hatch when "Fire Out" is heard

114
 

 zz

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Truck 4 Search and rescue, floor above fire

-Follow search pattern on floor, hit bu ers

-If victim is found, evacuate victim to 8th floor

BC 2 Division 10 Command

Engine 5 Lobby control

-Establish base outside of building

-Logistical support

-Check fire control room

Ambulance 4 Report to staging

Engine 6 Relieve back up line crew

Ambulance 5 Report to base

Engine 7 Search and rescue upper floor (13th)

-Follow search pattern on floor

-Gather all 20 markers

Ambulance 6 Report to base

Engine 8 Relieve 3rd line crew

Ambulance 7 Report to base

BC 3 Division 11 Command

Truck 5 Elevator/stairwell support

-Transport 35 air cylinders and 2 water coolers to staging

Ambulance 8 Report to base

Engine 9 Report to staging, tactical reserve

Ambulance 9 Report to base

BC 4 Ventilation group supervisor

Engine 10 Report to staging, tactical reserve

Engine 11 Report to base

Engine 12 Report to base

Truck 6 Relieve search and rescue crew on fire floor

-If victim is found, evacuate victim to 8th floor

BC 5 Report to staging

Truck 7 Search and rescue lower floor (9th)

-Follow search pattern on floor

-Gather all 20 markers

Truck 8 Relieve search and rescue crew on floor above fire

-If victim is found, evacuate victim to 8th floor

Truck 9 Report to staging, tactical reserve

Truck 10 Report to staging, tactical reserve

BC 6 Report to staging, tactical reserve

Truck 11 Report to base

Truck 12 Report to base

115
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 zz

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Company          Protocols: Crew Size of 6
 

COMPANY TASK ASSIGNMENTS

Engine 1 Assume command

-Access building keys

-Locate fire control room

-Check alarm panel

-Give command statement

-Check status of elevators

-Designate attack and evacuation stairwells

Join Engine 2 to form attack crew

-Connect to gated wye valve on 9th floor

-Advance attack line to 10th floor

-Simulate water on fire

-Maintain sustained attack

Truck 1 Establish Initial Rapid Intervention Crew

Once Rapid Intervention Team is established, begin search and rescue on fire floor

-Check for extension, complete 30 reps on weighted pike pole

-Follow search pattern on floor, hit bu ers

-If victim is found, evacuate victim to 8th floor

Ambulance 1 Establish firefighter rehab on 8th floor

Engine 2 Establish back up line

-Connect to gated wye valve on 9th floor

-Advance back up line to 10th floor

-Simulate water on fire

-Maintain sustained attack

Ambulance 2 Report to 8th floor staging area

-Package and transport Victim #1

Engine 3 Relieve attack line crew

Truck 2 Establish Rapid Intervention Team on 8th floor

Ambulance 3 Report to 8th floor staging area

-Package and transport Victim #2

BC 1 Incident Command

Engine 4 Establish 3rd line to floor above the fire

-Connect to standpipe on 11th floor

-Advance 3rd line to compartment above the fire

-Check for extension, complete 30 reps on weighted pike pole

Truck 3 Establish staging on 8th floor

Ventilation of attack stairwell

-Proceed to roof and burp hatch when "Fire Out" is heard

116
 

 zz

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Truck 4 Search and rescue, floor above fire

-Follow search pattern on floor, hit bu ers

-If victim is found, evacuate victim to 8th floor

BC 2 Division 10 Command

Engine 5 Lobby control

-Establish base outside of building

-Logistical support

-Check fire control room

Ambulance 4 Report to staging

Engine 6 Relieve back up line crew

Ambulance 5 Report to base

Engine 7 Search and rescue upper floor (13th)

-Follow search pattern on floor

-Gather all 20 markers

Ambulance 6 Report to base

Engine 8 Relieve 3rd line crew

Ambulance 7 Report to base

BC 3 Division 11 Command

Truck 5 Elevator/stairwell support

-Transport 35 air cylinders and 2 water coolers to staging

Ambulance 8 Report to base

Engine 9 Report to staging, tactical reserve

Ambulance 9 Report to base

BC 4 Ventilation group supervisor

Engine 10 Report to staging, tactical reserve

Engine 11 Report to base

Engine 12 Report to base

Truck 6 Relieve search and rescue crew on fire floor

-If victim is found, evacuate victim to 8th floor

BC 5 Report to staging

Truck 7 Search and rescue lower floor (9th)

-Follow search pattern on floor

-Gather all 20 markers

Truck 8 Relieve search and rescue crew on floor above fire

-If victim is found, evacuate victim to 8th floor

Truck 9 Report to staging, tactical reserve

Truck 10 Report to staging, tactical reserve

BC 6 Report to staging, tactical reserve

Truck 11 Report to base

Truck 12 Report to base

117
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Appendix B: Regression Coefficients (See Figures 57-59)B1. Regression Timings of Critical Tasks and Overall Time on Alarm Si e, Ascent Mode, and Crew Si

e

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B2. Regression Timings of Critical Tasks and Overall Time on Ascent Mode and Combinations of Alarm Size and Crew Size

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121
B3. Regression Timings of Critical Tasks and Overall Time on Combinations of Ascent Mode and Alarm Size

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123
 

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Appendix C: Comparisons Using Regression Results (Refer to Figures 65-85)
 

C1. Using Regression Results to Compare the Incremental Effects of Crew Si e on Critical Tasks
 

 ̃ What is the effect of adding to crew size?

4 vs. 3 5 vs. 4 6 vs. 5 5 vs. 3 6 vs. 4 

# Critical 

Task Outcome coeff.t signif.t coeff.t signif.t coeff.t signif.t coeff.t signif.t coeff.t signif.t

1

Advance 

Attack 

Line Begin -83 *** -64 ** -74 *** -147 *** -138 ***

2

Advance 

Second 

Line Begin -95 ** -114 *** -60 *** -208 *** -174 ***

3 Fire Out Begin -83 ** -64 ** -79 *** -147 *** -143 ***

5

Search 

and 

Rescue 

1Oth 

Floor Begin -83 ** -64 ** -79 *** -147 *** -143 ***

6

Victim #1

Found Begin -83 ** -64 ** -79 *** -147 *** -143 ***

7

Victim #1 

Rescue Begin -792 *** -727 *** -194 ** -1519 *** -921 ***

8

Victim #1 

Descent Begin -752 *** -709 *** -208 ** -1461 *** -917 ***

9

Primary 

Search 

11th 

Floor Begin -15 -94 *** 4 -109 *** -90 ***

1O

Victim #2 

Found Begin -40 -74 * -1 -114 ** -75 **

11

Victim #2 

Rescue Begin -882 *** -161 *** -7 -1043 *** -169 ***

12

Victim #2 

Descent Begin -866 *** -134 *** -38 -1000 *** -172 **

13

Advance 

Line 

Above 

Fire Begin -15 -98 *** -16 -113 *** -113 ***

1

Advance 

Attack 

Line Duration -20 -1 -26 * -21 * -27 *

2

Advance 

Second 

Line Duration 14 -50 -34 -35 -83 ***

3 Fire Out Duration -51 -11 -133 *** -63 -145 ***

4

Establish 

Stairwell

Support Duration -55 -68 -110 * -123 * -178 ***

5

Search 

and 

Rescue 

1Oth 

Floor Duration -598 *** -750 *** -97 -1348 *** -847 ***

6

Victim #1 

Found Duration -710 *** -663 *** -115 * -1372 *** -778 ***

7

Victim #1 

Rescue Duration 1 27 * -5 28 22 *

124
8

Vtcttm #1 

Descent Duration 33 ** -14 0 20 -14

9

Prtmary 

Search 

11th 

Floor Duration -556 *** -63 -154 ** -619 *** -217 ***

10

Vtcttm #2 

Found Duration -841 *** -88 ** -6 -929 *** -94 **

11

Vtcttm #2 

Rescue Duration 9 5 -4 14 1

12

Vtcttm #2 

Descent Duration -32 * 11 -40 ** -22 -29

13

Advance 

Ltne 

Above 

Ftre Duration -51 * -13 -24 -65 *** -37

14

All Tasks 

Complete 

 Ttmer 

Sheet Duration -719 *** -538 *** -121 -1257 *** -659 ***

1

Advance 

Attack 

Ltne End -103 ** -65 ** -101 *** -167 *** -165 ***

2

Advance 

Second 

Ltne End -80 -163 *** -94 ** -244 *** -257 ***

3 Ftre Out End -134 *** -75 -212 *** -209 *** -287 ***

4

Establtsh 

Statrrell

Support End -55 -69 -110 * -124 * -178 ***

5

Search 

and 

Rescue 

10th 

Floor End -681 *** -814 *** -177 -1495 *** -990 ***

6

Vtcttm #1 

Found End -792 *** -727 *** -194 ** -1519 *** -921 ***

7

Vtcttm #1 

Rescue End -791 *** -699 *** -199 ** -1490 *** -898 ***

8

Vtcttm #1 

Descent End -719 *** -722 *** -208 ** -1441 *** -931 ***

9

Prtmary 

Search 

11th 

Floor End -571 *** -157

10

Vtcttm #2 

Found -161

11

Vtcttm #2 

Rescue -156

12

Vtcttm #2 

Descent

** -150 ** -728 *** -308 ***

End -882 *** *** -7 -1043 *** -169 ***

End -873 *** *** -11 -1029 *** -168 **

End -898 *** -124 ** -78 -1021 *** -201 ***

13

Advance 

Ltne 

Above 

Ftre End -67 -111 *** -39 -178 *** -151 ***

14

All Tasks 

Complete End -719 *** -538 *** -121 -1257 *** -659 ***

(Timer 

Sheet)

t The coefficient (in seconds) shown for "X vs Y" represents the incremental effects of X relative to that of Y A negative coefficient value 

represents the time savings from X relative to Y A positive coefficient value represents a gain in time for X relative to Y 

* Legend: *** = significant at the O Ol ievei; ** = significant at the O OS ievei; * significant at the O lO ievei

125
           

             

What are the effects of alarm 

response and ascent mode?

high vs. low elevator vs. stairs

Task 

# Critical Task Outcome coeff.t signif.: coeff.t signif.:

1 Advance Attack Line Begin -18 -132 ***

2 Advance Second Line Begin 3 -126 ***

3 Fire Out Begin -21 -135 ***

5 Search and Rescue 10th Floor Begin -21 -135 ***

6 Victim #1 Found Begin -21 -135 ***

7 Victim #1 Rescue Begin 11 -103

8 Victim #1 Descent Begin 39 -122

9 Primary Search 11th Floor Begin -64 *** -149 ***

10 Victim #2 Found Begin -94 *** -179 ***

11 Victim #2 Rescue Begin -138 *** -87 **

12 Victim #2 Descent Begin -147 *** -129 ***

13 Advance Line Above Fire Begin -70 *** -162 ***

1 Advance Attack Line Duration -10 7

2 Advance Second Line Duration -38 * -13

3 Fire Out Duration 6 36

4 Establish Stairwell Support Duration -27 -610 ***

5 Search and Rescue 10th Floor Duration 35 -56

6 Victim #1 Found Duration 32 32

7 Victim #1 Rescue Duration 17 -8

8 Victim #1 Descent Duration -1 -161 ***

9 Primary Search 11th Floor Duration -37 0

10 Victim #2 Found Duration -44 92 **

11 Victim #2 Rescue Duration -4 6

12 Victim #2 Descent Duration 25 * -199 ***

13 Advance Line Above Fire Duration -25 6

14 All Tasks Complete (Timer Sheet) Duration -68 -254 ***

1 Advance Attack Line End -28 -125 ***

2 Advance Second Line End -35 -139 ***

3 Fire Out End -15 -98 ***

4 Establish Stairwell Support End -27 -610 ***

5 Search and Rescue 10th Floor End 14 -191 **

6 Victim #1 Found End 11 -103

7 Victim #1 Rescue End 28 -112

8 Victim #1 Descent End 38 -283 ***

C2. Using Regression Results to Compare

the Effects of Alarm Size and Ascent Mode

9 Primary Search 11th Floor End -101 ** -149 ***

10 Victim #2 Found End -138 *** -87 **

11 Victim #2 Rescue End -143 *** -81 *

12 Victim #2 Descent End -123 ** -329 ***

13 Advance Line Above Fire End -94 *** -157 ***

14 All Tasks Complete (Timer Sheet) End -68 -254 ***

t The coefficient (in seconds) shown for "X vs. Y" represents the incremental effects of X relative to that of Y. A 

negative coefficient value represents the time savings from X relative to Y. A positive coefficient value represents a 

gain in time for X relative to Y.

: Legend: *** = significant at the 0.01 level; ** = significant at the 0.05 level; * significant at the 0.10 level

126
           

             

           

ng Regression Results to Compare the What are the effects of a high response with lower crew size 

compared to a low response with higher crew size?

low/4 vs. high/3 low/5 vs. high/4 low/6 vs. high/5

Task 

#

C3. Usi

Effects of High Response with Lower Crew Size

to Low Response with Higher Crew Size

Critical Task Outcome coeff.t signif.: coeff.t signif.: coeff.t signif.:

1 Advance Attack Line Begin -93 • -57 • -28

2 Advance Second Line Begin -110 • -112 ••• -51

3 Fire Out Begin -93 • -57 • -28

5

Search and Rescue 10th 

Floor Begin -93 • -57 • -28

6 Victim #1 Found Begin -93 • -57 • -28

7 Victim #1 Rescue Begin -875 ••• -659 ••• -133

8 Victim #1 Descent Begin -857 ••• -694 ••• -181

9 Primary Search 11th Floor Begin 16 -34 102 ••

10 Victim #2 Found Begin 6 16 142 ••

11 Victim #2 Rescue Begin -737 ••• -50 125

12 Victim #2 Descent Begin -732 ••• -17 123

13 Advance Line Above Fire Begin 16 -39 93 ••

1 Advance Attack Line Duration -11 9 -16

2 Advance Second Line Duration 68 -1 -12

3 Fire Out Duration -61 -21 -135 ••

4 Establish Stairwell Support Duration -18 -59 -94

5

Search and Rescue 10th 

Floor Duration -647 ••• -718 ••• -119

6 Victim #1 Found Duration -783 ••• -602 ••• -105

7 Victim #1 Rescue Duration -3 11 -36

8 Victim #1 Descent Duration 47 -17 -13

9 Primary Search 11th Floor Duration -486 ••• -58 -150 •

10 Victim #2 Found Duration -743 ••• -65 -17

11 Victim #2 Rescue Duration -3 -8 17

12 Victim #2 Descent Duration -61 •• -31 -60 •••

13 Advance Line Above Fire Duration -14 25 -12

14

All Tasks Complete (Timer 

Sheet) Duration -729 ••• -462 •• 26

1 Advance Attack Line End -104 -48 -44

2 Advance Second Line End -42 -113 • -63

3 Fire Out End -154 • -78 -162 ••

4 Establish Stairwell Support End -18 -59 -94

5

Search and Rescue 10th 

Floor End -740 ••• -775 ••• -147

6 Victim #1 Found End -875 ••• -659 ••• -133

7 Victim #1 Rescue End -878 ••• -648 ••• -169

8 Victim #1 Descent End -810 ••• -711 ••• -194

9 Primary Search 11th Floor End -470 ••• -92 -48

10 Victim #2 Found End -737 ••• -50 125

11 Victim #2 Rescue End -740 ••• -57 142 •

12 Victim #2 Descent End -792 ••• -48 62

13 Advance Line Above Fire End 2 -14 81

14

All Tasks Complete (Timer 

Sheet) End -729 ••• -462 •• 26

t The coefficient (in seconds) shown for "X vs. Y" represents the incremental effects of X relative to that of Y. A 

negative coefficient value represents the time savings from X relative to Y. A positive coefficient value represents a 

gain in time for X relative to Y.

 * Legend: ••• = significant at the 0.01 level; •• = significant at the 0.05 level; • significant at the 0.10 level
       

       

       

C4. Using Regression Results to

Alarm Size and Ascent Mode

Compare the Effects of Combinations of

How do different combinations of ascent mode

 and alarm size affect timings?

elevator/low vs. 

stairs/low

stairs/high vs. 

stairs/low

elevator/high vs. 

elevator/low

 # Critical Task Outcome coeff.t signif.t coeff.t signif.t coeff.t signif.t

1 Advance Attack Line Begin -111 *** 3 -40

2 Advance Second Line Begin -108 *** 21 -15

3 Fire Out Begin -111 *** 3 -45 *

5 Search and Rescue 10th Floor Begin -111 *** 3 -45 *

6 Victim #1 Found Begin -111 *** 3 -45 *

7 Victim #1 Rescue Begin -97 17 4

8 Victim #1 Descent Begin -101 60 18

9 Primary Search 11th Floor Begin -146 *** -62 -67 ***

10 Victim #2 Found Begin -196 *** -112 * -77 ***

11 Victim #2 Rescue Begin -150 ** -201 *** -75

12 Victim #2 Descent Begin -187 ** -205 *** -89

13 Advance Line Above Fire Begin -153 *** -61 -78 ***

1 Advance Attack Line Duration 2 -15 -5

2 Advance Second Line Duration -9 -34 -41

3 Fire Out Duration 46 15 -4

4 Establish Stairwell Support Duration -686 *** -102 49

5 Search and Rescue 10th Floor Duration -163 -72 142

6 Victim #1 Found Duration 14 14 49

7 Victim #1 Rescue Duration -5 21 14

8 Victim #1 Descent Duration -180 *** -19 18

9 Primary Search 11th Floor Duration -55 -92 * 18

10 Victim #2 Found Duration 46 -90 * 2

11 Victim #2 Rescue Duration 6 -5 -4

12 Victim #2 Descent Duration -184 *** 40 * 9

13 Advance Line Above Fire Duration 18 -12 -37 *

14

All Tasks Complete (Timer 

Sheet) Duration -369 *** -183 * 48

1 Advance Attack Line End -108 *** -11 -45

2 Advance Second Line End -118 ** -13 -56

3 Fire Out End -65 18 -49

4 Establish Stairwell Support End -686 *** -102 49

5 Search and Rescue 10th Floor End -273 * -68 97

6 Victim #1 Found End -97 17 4

7 Victim #1 Rescue End -102 38 18

8 Victim #1 Descent End -281 ** 40 36

9 Primary Search 11th Floor End -202 *** -154 ** -49

10 Victim #2 Found End -150 ** -201 *** -75

11 Victim #2 Rescue End -145 ** -207 *** -79

12 Victim #2 Descent End -371 *** -165 ** -81

13 Advance Line Above Fire End -135 *** -73 -116 ***

14

All Tasks Complete (Timer 

Sheet) End -369 *** -183 * 48

t The coefficient (in seconds) shown for "X vs. Y" represents the incremental effects of X relative to that of Y. A 

negative coefficient value represents the time savings from X relative to Y. A positive coefficient value represents a 

gain in time for X relative to Y.

 : Legend: *** = significant at the 0.01 level; ** = significant at the 0.05 level; * significant at the 0.10 level

128
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on Dura End 

130
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Enb

131
   

     

                     

                   

             

               

                   

                 

                     

                 

                       

                   

                   

                     

               

                     

                       

                   

                   

                     

                         

                   

                         

                   

                   

                   

                         

               

                             

                         

               

                   

                     

                 

                   

                     

                     

                   

                 

                                       

Appendix D: Detailed Regression Results
 

Effects of Crew Size

In this section, the results of the regression analyses are used to

identify and discuss findings regarding the effect of crew size on

critical tasks. Appendix C1 reconfigures the earlier regression

results (Appendices B1­B3) for an analysis of the incremental

effect of crew size on critical tasks. These results were assembled

into separate tables reflecting the three timing outcomes in this

study – begin time, duration, and end time. In this synthesis, three

tables are provided, one for each outcome type (begin, duration,

end). Table 17 presents the effect on time to begin a critical task

when crew size is incremented by one or two firefighters. Note

that these results control for (i.e., remove the effects of) ascent

mode and alarm size, so the results indicate the net impact of

crew size change. The leftmost three­column set shows the

decrease in task begin times when a single firefighter is added to

crews of 3, 4 and 5. Generally, going from a 3­person to a

4­person crew size has a large impact on Advancing the Attack

Line, backing it up by Advancing a Second Line, and commencing

Search and Rescue of the 10th Floor. Reductions are in the range

of 1 1⁄2 min. Increases in crew size from 4 to 5 see significant

reductions in all of the critical task begin times, with reductions

ranging between 1 min and 2 min. Raising crew size from 5 to 6

shows significant time reductions of just over 1 min for Advance

Attack Line, Advance Second Line, and Search and Rescue of the

10th Floor. As one might expect, increasing crew sizes by 2

firefighters from 3 to 5 or from 4 to 6 results in the largest

improvements in begin times for critical tasks. Reductions range

from a low of 1 min (for Advance Second Line 6 vs. 5 crew size) to

25 min (for Victim #1 Rescue for 5 vs. 3 crew size). These findings

suggest that meaningful improvements in critical task start times

can be attained when adding a single firefighter to a crew

regardless of the current crew size (under 6), and the benefits in

time reduction continue when adding 2 firefighters to a crew.

Next, the effects of incrementing crew size on the duration of

critical tasks are examined. The duration is the time it takes to

complete a task once it commences. Table 18 presents the result of

this analysis, controlling for ascent mode and alarm size. It is

apparent that incrementing crew size by one firefighter (see the

 What is the effect of adding to crew size on BEGIN time?

4 vs. 3 5 vs. 4 6 vs. 5 5 vs. 3 6 vs. 4

OutcoEe Critical =asks coeff.

t

Signif

 *

coeff.

t

Signif

 *

coeff.

t

Signif

 *

coeff.

t

Signif

 *

coeff.

t

Signif 

*

IwC z =iEe

Advance 

Attack Line -83 ** -64 ** -74 *** -147 *** -138 ***

Advance 

Second Line -95 ** -114 *** -60 *** -208 *** -174 ***

Fire Out -83 ** -64 ** -79 *** -147 *** -143 ***

Search and 

Rescue 10th 

Floor -83 ** -64 ** -79 *** -147 *** -143 ***

Victim #1 

Found -83 ** -64 ** -79 *** -147 *** -143 ***

Victim #1 

Rescue -792 *** -727 *** -194 **

-

1519 *** -921 ***

Victim #1 

Descent -752 *** -709 *** -208 **

-

1461 *** -917 ***

Primary 

Search 11th 

Floor -15 -94 *** 4 -109 *** -90 ***

Victim #2 

Found -40 -74 * -1 -114 ** -75 **

Victim #2 

Rescue -882 *** -161 *** -7

-

1043 *** -169 ***

Victim #2 

Descent -866 *** -134 *** -38

-

1000 *** -172 **

Advance 

Line Above 

Fire -15 -98 *** -16 -113 *** -113 ***

t The coefficient represents the effect of adding a single crew member, i.e., X+1 vs. X. A negative coefficient represents the time 

savings in seconds from adding a firefighter to the crew size. A positive coefficient represents a gain in time by adding a firefighter to 

a crew.

‡ Legend: *** = significant at the 0.01 level; ** = significant at the 0.05 level; * significant at the 0.10 level

Table 17: Effects of incrementing crew size on begin time, controlling for ascent mode and alarm size; coefficients are in seconds

132
                                         

                   

               

                       

                   

                     

                     

                           

               

                       

                 

               

                   

                               

                   

                 

                             

                   

                 

                   

                       

                   

                     

                         

                     

                   

                   

                       

                 

                       

                       

                   

               

                           

                       

leftmost three row sets) has a negligible effect on duration for

Advance Attack Line, Advance Second Line, Fire Out, and

Establish Stairwell Support when going from 3 to 4 and from 4 to

5 crew size. Small improvements (roughly 2 min) for these tasks

occur when going from 5 to 6 crew size. In contrast, sizeable

improvements of 10 min to 12.5 min are seen for Search and

Rescue 10th Floor when going from 3 to 4 and from 4 to 5 crew

sizes. Similar­sized reductions in time occur for Primary Search of

Floor 11 when going from 3 to 4 crew size. The cumulative effects

of incrementing crew size by one firefighter are seen in the

bottom row of the leftmost three­column set. Overall duration

times decreased by an average of 12 min when increasing crew

size from 3 to 4, by 9 min when going from 4 to 5 crew size, and

by 2 min when increasing crew size from 5 to 6.

The rightmost two row sets present the effect of incrementing

crew size by two firefighters when going from 3 to 5 or from 4 to 6

crew sizes. When going from 3 to 5 crew size, significant

reductions in duration times occurred in the later tasks: Search

and Rescue 10th Floor witnessed an average 22 1⁄2 min reduction,

Search of Floor 11 saw roughly a 10 1⁄2 min reduction, and Overall

Response Time saw an average 21 min decrease. The differences in

task duration times between crew sizes of 4 and 6 were substantial

but generally not nearly as large as between crew sizes of 3 and 5.

Next the effect of incrementing crew size on the end times of

critical tasks is examined. Results are presented in Table 19. Due

most likely to the cumulative benefits of time savings over the

course of the full task set, about three quarters of the observed end

time reductions on critical task end times are statistically significant

when incrementing crew size by a single firefighter (i.e., 3 to 4, 4 to

5, and 5 to 6). The largest time improvements are seen when going

from crew size 3 to 4 (see the leftmost column set).

As firefighter crews navigate the later tasks, the improvements reach

the 10 min to 15 min range (e.g.,see the set of Victim #2 tasks).Very

large gains are seen for the 10th Floor Search and Victim #1 Rescue

 What is the effect of adding to crew size on task DURATION time?

4 vs. 3 5 vs. 4 6 vs. 5 5 vs. 3 6 vs. 4 

0utcoEe Critical Task coeff.

t

Signi 

f.‡ 

coeff.

t

Signi 

f. ‡ 

coeff.

t

Signi 

f. ‡ coeff.t Signi f. ‡ 

coeff.

t

Signi 

f. ‡ 

c:c<T 0z TiEe

Advance 

Attack Line -20 -1 -26 * -21 * -27 *

Advance 

Second Line 14 -50 -34 -35 -83 ***

Fire Out -51 -11 -133 *** -63 -145 ***

Establish 

Stairwell 

Support -55 -68 -110 * -123 * -178 ***

Search and 

Rescue 1Oth 

Floor -598 *** -750 *** -97 -1348 *** -847 ***

Victim #1 

Found -710 *** -663 *** -115 * -1372 *** -778 ***

Victim #1 

Rescue 1 27 * -5 28 22 *

Victim #1 

Descent 33 ** -14 0 20 -14

Primary 

Search 11th 

Floor -556 *** -63 -154 ** -619 *** -217 ***

Victim #2 

Found -841 *** -88 ** -6 -929 *** -94 **

Victim #2 

Rescue 9 5 -4 14 1

Victim #2 

Descent -32 * 11 -40 ** -22 -29

Advance Line 

Above Fire -51 * -13 -24 -65 *** -37

All Tasks 

Complete 

(Timer Sheet) -719 *** -538 *** -121 -1257 *** -659 ***

t The coefficient represents the effect of adding a single crew member, i.e., X+1 vs. X. A negative coefficient represents the time 

savings in seconds from adding a firefighter to the crew size. A positive coefficient represents a gain in time by adding a firefighter to 

a crew.

‡ Legend: *** = significant at the O.O1 level; ** = significant at the O.OS level; * significant at the O.1O level

Table 18: Effects of incrementing crew size on task duration time, controlling on ascent mode and alarm size; coefficients are in seconds

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tasks (over 11 min) when incrementing crew size from 4 to 5. The

improvements in All Tasks Complete end times are substantial (9 1⁄2

min to 12 min) when incrementing crew size from 3 to 4 or from 4

to 5. Reductions of end time All Tasks Complete are modest to

minor when incrementing crew size from 5 to 6.

Turning to crew increments of 2 firefighters, Table 19 shows

sizeable, significant improvements in end time for virtually every

critical task (see rightmost two column sets). Modest

improvements in the 2 min to 4 min range are seen in the earlier

critical tasks (Advance Attack Line through Establish Stairwell

Support). For the remainder of the critical tasks, large reductions

in end times (ranging from 12 min to 25 min) are seen for all but

one task (Advance Fire Line Above Fire) when incrementing crew

size from 3 to 5. Even incrementing from 4 to 6 crew size shows

significant albeit smaller improvements of 15 min for the Search

and Victim #1 Rescue collection of tasks, and roughly 3 min to 5

min reductions for the tasks related to Floor 11 and Victim #2

Rescue. The overall reduction in end time is over 20 min when

incrementing crew size from 3 to 5, and over 10 min when

increasing crew size from 4 to 6.

The findings from the crew size analysis suggest that size does

matter when it comes to the number of firefighters assigned to

crews. Even the increment of a single firefighter can have a positive

impact on the start, duration and completion of varied critical

tasks. And incrementing crew size by two is also beneficial. The

most sizeable improvements were seen when incrementing from a

smaller crew size to a larger crew size, e.g., 3 to 4, 4 to 5, or 3 to 5.

Effects of Alarm Size and Ascent Mode

Next the effects of alarm response (high, low) and ascent mode

(elevator, stairs) on critical task timings are explored. Appendix

C2 uses the results of regression to compare high and low alarm

response times and to compare elevator to stair response times for

all critical tasks and associated outcomes. Because alarm response

and ascent mode are design factors built into the field experiment

in order to examine crew size effects, a summary is provided in

this section rather than a detailed assessment of the findings. With

regard to alarm response, about one third of the 27 distinct

What is the effect of adding to crew size on END time?

4 vs. 3 5 vs. 4 6 vs. 5 5 vs. 3 6 vs. 4 

OutcoEe Critical Tasks coeff.

t

Signi 

f.‡ 

coeff.

t

Signi 

f.‡ 

coeff.

t

Signi 

f.‡ coeff.t Signi f.‡ 

coeff.

t

Signi 

f.‡ 

wzc TiEe

Advance 

Attack Line -103 ** -65 ** -101 *** -167 *** -165 ***

Advance 

Second Line -80 -163 *** -94 ** -244 *** -257 ***

Fire Out -134 *** -75 -212 *** -209 *** -287 ***

Establish 

Stairwell 

Support -55 -69 -110 * -124 * -178 ***

Search and 

Rescue 10th 

Floor -681 *** -814 *** -177 -1495 *** -990 ***

Victim #1 

Found -792 *** -727 *** -194 ** -1519 *** -921 ***

Victim #1 

Rescue -791 *** -699 *** -199 ** -1490 *** -898 ***

Victim #1 

Descent -719 *** -722 *** -208 ** -1441 *** -931 ***

Primary Search 

11th Floor -571 *** -157 ** -150 ** -728 *** -308 ***

Victim #2 

Found -882 *** -161 *** -7 -1043 *** -169 ***

Victim #2 

Rescue -873 *** -156 *** -11 -1029 *** -168 **

Victim #2 

Descent -898 *** -124 ** -78 -1021 *** -201 ***

Advance Line 

Above Fire -67 -111 *** -39 -178 *** -151 ***

All Tasks 

Complete 

(Timer Sheet) -719 *** -538 *** -121 -1257 *** -659 ***

t The coefficient represents the effect of adding a single crew member, i.e., X+1 vs. X. A negative coefficient represents the time

savings in seconds from adding a firefighter to the crew size. A positive coefficient represents a gain in time by adding a firefighter to a 

crew.

‡ Legend: *** = significant at the 0.01 level; ** = significant at the 0.0S level; * significant at the 0.10 level

Table 19: Effects of incrementing crew size on task end time, controlling for ascent mode and alarm size; coefficients are in seconds

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outcome­task comparisons between high and low response were

statistically significant. Six of the seven significant differences

between high and low alarm sizes involved reductions of the end

time of tasks, ranging from 1 1⁄2 min to 2 1⁄2 min smaller for the

high response. These task end times involved Search of Floor 11,

the three rescue tasks related to Victim #2 (Find, Rescue, Descent)

and Advancing Line Above Fire.

Comparing elevator to stair ascent, statistically significant

reductions in time were seen in favor of elevator use for over two

thirds of the critical task outcomes. The most sizeable time

reduction for the elevator was for Establishing Stairwell Support

(duration and end time reductions of about 10 min). Other notable

reductions in favor of elevator were for the end times of Descent for

Victim #1 (4 min 42 s) and Victim #2 (5 1⁄2 min). When other

significant reductions occurred they were smaller, in the range of

about 1 1⁄2 min to 4 min (see Appendix C2 for details).

The assessment of alarm size and ascent mode confirmed the

logical direction of differences when they were found to exist.

Illogical timing patterns (i.e., smaller times for low alarm size

than for high or smaller times for stairs than for elevators) were

not observed.

Combined Effects of Alarm Size and Crew Size

Given the findings from the crew size analysis that adding one or

two firefighters to a crew can generally achieve substantial task

time decreases, a logical question is whether the meaningful

benefits of a higher crew size could be realized by implementing a

higher alarm response at a smaller crew size (e.g., 4/high

compared to 5/low). The hope might be that a high response with

a lower crew size might yield similar results in task timing to that

of a low response with higher crew size. This issue is explored in

the following analysis.

Appendix C3 presents regression results that compare the effect

of high response with lower crew size compared to a low response

with higher crew size. These results were used to compile separate

summary tables for begin, duration, and end times. Table 20

provides a summary of findings for tasks deemed critical for

begin times. The leftmost two column sets show that statistically

significant begin times occurred for low alarm responses with 4 or

5 crew size compared to smaller sized counterparts – high

response with crew sizes of 3 and 4, respectively. There are

significant reductions in begin times for all critical tasks from

Advance Attack Line through Victim #1 Descent. Sizeable

reductions of about 12 min are also seen for Victim #2 Rescue and

Descent. This suggests that a low alarm response with crews of

size 4 or 5 outperforms a high alarm response with crew sizes

smaller by one firefighter. When time decreases occur they are in

the range of 1 min to just under 2 min.

It is noteworthy that this pattern does not hold for a low response

with crew size 6 compared to a high response with crew size 5. The

observed differences in task begin times were significantly higher

for Primary Search of Floor 11 and Advance Line Above Fire.

Table 20: Contrasting high response to low response with smaller crew sizes for begin times; coefficients are in seconds

What are the BEGIN time effects of a high response 

with lower crew size compared to a low response with 

higher crew size?

low/4 vs. high/3 low/5 vs. high/4 low/6 vs. high/5

OutcoEe Critical Tasks coeff.t Signif. 

‡ coeff.t Signif.‡ coeff.t Signif. ‡

Advance Attack Line -93 * -57 * -28

Advance Second Line -110 * -112 *** -51

Fire Out -93 * -57 * -28

Search and Rescue 10th Floor -93 * -57 * -28

Victim #1 Found -93 * -57 * -28

Victim #1 Rescue -875 *** -659 *** -133

Victim #1 Descent -857 *** -694 *** -181

Primary Search 11th Floor 16 -34 102 **

Victim #2 Found 6 16 142 **

Victim #2 Rescue -737 *** -50 125

Victim #2 Descent -732 *** -17 123

aw� z TiEe

Advance Line Above Fire 16 -39 93 **

t The coefficient represents the effect of a low alarm response with a larger crew (larger by 1 firefighter) relative to a higher alarm 

response but with a crew size that is smaller by one firefighter. The contrast shown is the first scenario relative to the second: the 

coefficient for "X vs. Y" is (X-Y). A negative coefficient represents the time savings in seconds from a larger crew with a lower alarm 

response. A positive coefficient represents a gain in time from a larger crew with a lower alarm response.

‡ Legend: BBB = significant at the 0.01 level; BB = significant at the 0.05 level; t significant at the 0.10 level

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Next duration is examined. Table 21 provides a summary of

findings for tasks deemed critical for duration times. Although less

than a third of these comparisons were statistically significant, they

tended to be prominent when they occurred. For Search of the

10th Floor and Victim #1 Rescue, a low response with crew size 4

showed about 11 min to 13 min reductions compared to that of a

high response with crew size 3. And for low response crew size 5

the duration time reductions were 10 min to 13 min compared to a

high response with crew size 4. The low/4 combination revealed an

8 min reduction in duration time for Search of Floor 11 and about

a 12 min reduction for Victim #2 Rescue compared to a high

response with crew size 3. Similarly large reductions in duration

time appear for All Tasks Complete under these two response crew

size scenarios. The low/6 combination shows three significant

duration reductions compared to high/5: a 2.2 min reduction for

Fire Out, a 2 1⁄2 min reduction for Search of Floor 11, and a 1 min

reduction for Victim #2 Descent.

Finally, the end time comparisons for this analysis are examined.

Table 22 presents critical task end time contrasts of low alarm

response to that of a high response with one less crew on staff.

Over half of the task end time comparisons were statistically

significant when testing the low/4 and low/5 combinations against

their counterparts (i.e., high/3 and high/4, respectively). When

significant, low response with crew sizes 4 and 5 displayed task

end time reductions of 2.6 min to well over 14 min. The low/4

combination showed significant end time reductions compared to

high/3 for 11 of the 14 critical tasks in this analysis (see leftmost

column set of Table 22). For the low/5 combination, 6 of 14 tasks

showed significant reductions in end time compared to high/4

(see middle column set in figure). Only 2 of 14 tasks exhibited

significantly lower end times for the low/6 combination relative to

that of high/5 (as shown in the rightmost column set of the table).

Generally, for critical task end times, reductions were most

pronounced when comparing low/4 to high/3, followed by low/5

compared to high/4. The low/6 combination featured the smallest

reductions compared to the high/5.

In summary, the analysis of the alarm response and crew size

combinations suggests that the benefits of crew size increases (in

terms of reduced begin, duration, and end times for critical tasks)

are fairly robust. Low alarm response with a higher crew size tends

to be more favorable in critical task timings than the

corresponding timings for a high alarm response with a crew size

of one less firefighter.

Combined Effects of Alarm Size and Ascent

The effects of different combinations of alarm size (high, low) and

ascent mode (stairs, elevator) are now examined. This combination

of variables is important to understand the synergies that may exist

What are the effects on DURATION of a high response 

with lower crew size compared to a low response with 

higher crew size?

low/4 vs. high/3 low/5 vs. high/4 low/6 vs. high/5

0utcoEe Critical =asks coeff.t Signif.‡ coeff.t Signif.‡ coeff.t Signif.‡ c:c<=i0z =iEe

Advance Attack Line -11 9 -16

Advance Second Line 68 -1 -12

Fire Out -61 -21 -135 **

Establish Stairwell Support -18 -59 -94

Search and Rescue 10th Floor -647 *** -718 *** -119

Victim #1 Found -783 *** -602 *** -105

Victim #1 Rescue -3 11 -36

Victim #1 Descent 47 -17 -13

Primary Search 11th Floor -486 *** -58 -150 *

Victim #2 Found -743 *** -65 -17

Victim #2 Rescue -3 -8 17

Victim #2 Descent -61 ** -31 -60 ***

Advance Line Above Fire -14 25 -12

All Tasks Complete (Timer Sheet) -729 *** -462 ** 26

t The coefficient represents the effect of a low alarm response with a larger crew (larger by 1 firefighter) relative to a higher alarm 

response but with a crew size that is smaller by one firefighter. The contrast shown is the first scenario relative to the second: the 

coefficient for "X vs. Y" is (X-Y). A negative coefficient represents the time savings in seconds from a larger crew with a lower alarm 

response. A positive coefficient represents a gain in time from a larger crew with a lower alarm response.

‡ Legend: BBB = significant at the 0.01 level; BB = significant at the 0.05 level; B significant at the 0.10 level

Table 21: Contrasting high response to low response with smaller crew sizes for duration times; coefficients are in seconds

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on the fire ground.Appendix C4 presents regression results that

contrast several of combinations of alarm size and ascent mode.

Three scenarios were contrasted in the appendix:

n elevator/low vs.stairs/low — this comparison addresses the

relative gains or losses in time when the alarm size is low and

firefighters are faced with stairs or elevator ascent;

n stairs/high vs.stairs/low — this scenario focuses on stair

ascent and examines the impact of high versus low alarm size;

n elevator/high vs. elevator/low — this is the complement to

the second scenario — it focuses on elevator ascent and

explores the effects of high versus low alarm size.

Elevator/low vs.stairs/low. The leftmost column set of

Appendix C4 contrasts the critical task timings for elevator ascent

with a low alarm size to stair ascent with similarly low alarm size.

Elevator ascent significantly reduces all begin times and most end

times compared to stair ascent. Most of the reductions due to

elevator ascent are in the 2 min to 4 min range, with a few

obvious exceptions. Elevator ascent allows Establishment of

Stairwell Support more than 11 min more quickly than stair

ascent. Both Victim #2 Descent and All Task Complete occur

more than 6 min quicker for elevator ascent. Except for

Establishment of Stairwell Support, there are no ascent mode

differences for task duration. This also makes sense, since crew

size is controlled in these comparisons.

Stairs/high vs.stairs/low. The middle column set of Appendix

C4 presents the effects of high versus low alarm size when

firefighters are faced with stair ascent. The alarm size is seen to

have virtually no effect for critical task timings except for tasks

related to Search of Floor 11 (duration and end) and Victim #2

Found, Rescue and Descent. High alarm size realized a mean

reduction in the range of 1 1⁄2 min to 3 min 24 s for these tasks. All

Tasks Complete was also significantly smaller for high alarm size

by 3 min. No other task timing comparisons were statistically

different.

Elevator/high vs. elevator/low. The rightmost column set of

Appendix C4 presents the effects of high versus low alarm size

when firefighters employ elevator ascent. High alarm size led to

only eight significantly lower timings than a low alarm size: 45 s

reductions in begin time for Fire Out, Search of Floor 10, and

Victim #1 Found; small reductions of just over 1 min in begin

times for Search of Floor 11 and Victim #2 Found, and small

reductions for begin, duration, and end times related to the

Advancement of Line Above the Fire. Timing reductions were in

the range of just over 30 s to just under 2 min. No other task

timing comparisons were statistically different.

What are the effects on END time of a high response 

with lower crew size compared to a low response 

with higher crew size?

low/4 vs. high/3 low/5 vs. high/4 low/6 vs. high/5

OutcoEe Critical Tasks coeff.t Signif.‡ coeff.t Signif.‡ coeff.t Signif.‡ wzc TiEe

Advance Attack Line -104 -48 -44

Advance Second Line -42 -113 * -63

Fire Out -154 * -78 -162 **

Establish Stairwell Support -18 -59 -94

Search and Rescue 10th Floor -740 *** -775 *** -147

Victim #1 Found -875 *** -659 *** -133

Victim #1 Rescue -878 *** -648 *** -169

Victim #1 Descent -810 *** -711 *** -194

Primary Search 11th Floor -470 *** -92 -48

Victim #2 Found -737 *** -50 125

Victim #2 Rescue -740 *** -57 142 *

Victim #2 Descent -792 *** -48 62

Advance Line Above Fire 2 -14 81

All Tasks Complete (Timer Sheet) -729 *** -462 ** 26

t The coefficient represents the effect of a low alarm response with a larger crew (larger by 1 firefighter) relative to a higher alarm 

response but with a crew size that is smaller by one firefighter. The contrast shown is the first scenario relative to the second: the 

coefficient for "X vs. Y" is (X-Y). A negative coefficient represents the time savings in seconds from a larger crew with a lower alarm 

response. A positive coefficient represents a gain in time from a larger crew with a lower alarm response.

‡ Legend: BBB = significant at the 0.01 level; BB = significant at the 0.05 level; B significant at the 0.10 level

Table 22: Contrasting high response to low response with smaller crew sizes for end times; coefficients are in seconds

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Appendix E: Time-to-Task Percentage Tables
 

How to Interpret Percentage Tables

The results from the time­to­task analyses can be displayed in a

number of ways. Of particular interest in this study is the difference

in the time it takes firefighters using different crew sizes (or alarm

sizes or vertical response mode) to complete a given task or to reach a

certain milestone. Table 23 represents the raw time data (minutes and

seconds) to complete one of the tasks in the experiments.

Crew Size Time to complete task 

3-person A min A s 

4-person B min B s 

5-person C min C s 

6-person D min D s 

Table 23: Times for each crew size to complete a task

A comparison between times for different crew sizes can be

presented as an array of differences between the time it takes one

crew size to complete a task and the time it takes another crew size to

complete the same task. Table 24 displays a sample matrix in which

the time taken by the crew size listed in each row has been subtracted

from the time taken by the crew size listed in the column. So if a

Crew Size 3-person 4-person 5-person 6-person 

3-person -(X min X s) -(Y min Y s) -(Z min Z s) 

4-person X min X s -(Q min Q s) -(R min R s) 

5-person Y min Y s Q min Q s -(S min S s) 

6-person Z min Z s R min R s S min S s 

Table 24: Array of time differences.

3­person crew took A min A s and a 6­person crew took D min D s to

complete the task, the value shown in row 6­person/column 3­person

is equal to (A min A s) – (D min D s) = (Z min Z s). The value in row

3­person/column 6­person is the negative of this value, (D min D s) –

(A min A s) = ­ (Z min Z s). Since the task time tends to decrease as

the number of persons on the crew increases, the numbers below the

diagonal cells of the matrix are generally positive indicating a

decrease in time­to­task or faster performance times. Likewise, the

cells above the diagonal cells in the matrix are generally negative

indicating slower performance times. The values in the cells along the

diagonal are equal to zero.

Although the tasks carried out in this study are intended to be

representative of tasks on a real fireground, the time required to

complete a task will be dependent on the circumstances of the

individual fire. Of greater meaning for comparing one crew size

against another, or one mode of vertical response to another, is the

change in time relative to the total time required for the task. This is

most easily expressed as a percentage: 100 × the difference in time

divided by the total time required by the base scenario. The selection

of the base scenario depends on the change in crew size being

compared.

In Table 25, time­to­task percentages are calculated as the time

differences in Table 24 divided by the total time taken to complete the

task by the crew size in that column (from Table 23). Note that the

values in corresponding cells above and below the diagonal (e.g.,

3­person row/6­person column vs. 6­person row/3­person column)

are no longer the same value with different sign. Their values have

been changed by calculations using different denominators based on

actual performance times in the study.

Crew Size 3-person 4-person 5-person 6-person 

3-person -100 (X min X s)

 B min B s 

-100 (Y min Y s)

 C min C s 

-100 (Z min Z s)

 D min D s 

4-person 100 X min X s

 A min A s 

-100 (Q min Q s)

 C min C s 

-100 (R min R s)

 D min D s 

5-person 100 Y min Y s

 A min A s 

100 Q min Q s

 B min B s 

-100 (S min S s)

 D min D s 

6-person 100 Z min Z s

 A min A s 

100 R min R s

 B min B s 

100 S min S s

 C min C s 

Table 25: Calculations of time­to­task percentages

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Table 26 shows an example from the time­to­task percentage

tables presented in this appendix. Note that the values in cells

above the diagonal are higher than their counterparts below the

diagonal. This is because the total time­to­task completion

decreases with larger crew size, making the denominator larger

and thus the percentage smaller for cells below the diagonal.

The value in each cell can be described as the percentage that the

crew size in the row differs from the crew size in the column

(which is the base for the comparison).

The advantage of displaying the results in this manner is that it

provides answers to questions about the impact of changing the

crew size on the completion of fireground tasks. For example, if a

fire department that staffs with 4­person crews is interested in the

effect of going to a different crew size, they can look down the

4­person column (indicated by the arrow in Table 26) and see

that, according to this study, a 5­person crew would complete this

task 6.7 % faster and a 6­person crew 14.5 % faster than the

4­person crew. A 3­person crew would be 8.7 % slower, as

indicated by the negative sign in the table.

Crew Size 3-person 4-person 5-person 6-person 

3-person -8.7 -16.5 -27.1 

4-person 8.0 -7.2 -16.9 

5-person 14.2 6.7 -9.1 

6-person 21.3 14.5 8.3 

Table 26: Sample time­to­task percentage table.

Time­to­Task: Percentage Tables by Task

The following tables present time­to­task percentages for the

critical tasks in this study. The start times, durations, and end

times used in calculations are the same as those shown in related

Crew Size 3-person 4-person 5-person 6-person 

3-person -23.7 -50.4 -58.0 

4-person 19.2 -21.6 -27.7 

5-person 33.5 17.7 -5.1 

6-person 36.7 21.7 4.8 

Positive numbers indicate % faster; negative numbers indicate % slower

Table 27: Percentage Table for Overall Time­to­Task Completion by

Crew Size (see Figure 57)

figures in Section 9.4 Regression Analyses and Chapter 10

Time­to­Task Results. Positive percentage values in these tables

indicate that the scenario given by the row is faster than the

scenario given by the column and negative numbers indicate the

percentage given by the row is slower than the scenario given by

the column.

Most time­to­task percentage tables compare results due to

various crew sizes only, with results for other effects included in

the averaging. For Overall Time­to­Task Completion, percentage

differences due to vertical ascent mode (stair or elevator) or to

high or low alarm size are listed in addition to crew size.

Overall Time­to­Task Completion

The following two tables show results from multiple factors.

Table 28 displays the Overall Time­to­Task Completion for crew

size and vertical ascent model, either stair or elevator. The

headings are abbreviated with the number in the crew and S or E

for stairs or elevator, respectively. This table allows a quantitative

comparison of the effects from using stairs or elevators for each

crew size.

Crew 

Size 3S 3E 4S 4E 5S 5E 6S 6E 

3S -7.7 -23.8 -33.1 -46.0 -67.2 -57.8 -70.4 

3E 7.1 -15.0 -23.6 -35.6 -55.3 -46.5 -58.2 

4S 19.2 13.0 -7.5 -18.0 -35.1 -27.4 -37.6 

4E 24.8 19.1 7.0 -9.8 -25.7 -18.6 -28.1 

5S 31.5 26.3 15.2 8.9 -14.5 -8.0 -16.7 

5E 40.2 35.6 26.0 20.4 12.7 5.7 -1.9 

6S 36.6 31.7 21.5 15.7 7.4 -6.0 -8.0 

6E 41.3 36.8 27.3 21.9 14.3 1.8 7.4 

Table 28: Percentage Table for Overall Time­to­Task Completion by

Crew Size and Stair/Elevator Ascent Mode (see Figure 58)

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Table 29 displays the Overall Time­to­Task for crew size and high

or low alarm size. The headings are abbreviated with the number

in the crew and L or H for low or high alarm size, respectively.

This table allows a quantitative comparison of the effects from

alarm size for each crew size.

Crew 

Size 3L 3H 4L 4H 5L 5H 6L 6H 

3L 1.5 -22.0 -23.5 -45.8 -52.7 -51.2 -62.8 

3H -1.6 -23.9 -25.4 -48.1 -55.1 -53.5 -65.3 

4L 18.0 19.3 -1.2 -19.5 -25.2 -23.9 -33.4 

4H 19.0 20.2 1.2 -18.1 -23.7 -22.4 -31.8 

5L 31.4 32.5 16.3 15.3 -4.8 -3.7 -11.6 

5H 34.5 35.5 20.1 19.2 4.5 1.0 -6.6 

6L 33.9 34.9 19.3 18.3 3.6 -1.0 -7.6 

6H 38.6 39.5 25.1 24.1 10.4 6.1 7.1 

Table 29: Percentage Table for Overall Time­to­Task Completion by Crew Size and High/Low

Alarm Size (see Figure 59)

Advance Attack Line: Begin time, duration, and end time

Crew Size 3-person 4-person 5-person 6-person 

3-person -8.7 -16.52 -27.08 

4-person 8 -7.19 -16.91 

5-person 14.18 6.71 -9.07 

6-person 21.31 14.47 8.31 

Crew Size 3-person 4-person 5-person 6-person 

3-person -12.93 -13.7 -39.5 

4-person 11.45 -0.68 -23.53 

5-person 12.05 0.68 -22.69 

6-person 28.31 19.05 18.49 

Table 30: Percentage Table for Advance Attack Line begin time Table 32: Percentage Table for Advance Attack Line end time

(See Figure 70) (See Figure 70)

Crew Size 3-person 4-person 5-person 6-person 

3-person -12.93 -13.7 -39.5 

4-person 11.45 -0.68 -23.53 

5-person 12.05 0.68 -22.69 

6-person 28.31 19.05 18.49 

Table 31: Percentage Table for Advance Attack Line duration

(See Figure 70)

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Advance Second Line: Begin time, duration, and end time

Crew Size 3-person 4-person 5-person 6-person 

3-person -8.9 -22.0 -30.2 

4-person 8.1 -12.0 -19.6 

5-person 18.0 10.8 -6.8 

6-person 23.2 16.4 6.3 

Table 33: Percentage Table for Advance Second Line begin time

(See Figure 71)

Crew Size 3-person 4-person 5-person 6-person 

3-person 5.3 -16.3 -38.1 

4-person -5.6 -22.8 -45.9 

5-person 14.0 18.6 -18.8 

6-person 27.6 31.4 15.8 

Table 34: Percentage Table for Advance Second Line duration

(See Figure 71)

Crew Size 3-person 4-person 5-person 6-person 

3-person -6.1 -21.0 -31.7 

4-person 5.8 -14.0 -24.1 

5-person 17.4 12.3 -8.8 

6-person 24.1 19.4 8.1 

Table 35: Percentage Table for Advance Second Line end time

(See Figure 71)

Fire Out: Begin time, duration, and end time

Crew Size 3-person 4-person 5-person 6-person 

3-person -8.7 -16.5 -27.9 

4-person 8.0 -7.2 -17.6 

5-person 14.2 6.7 -9.7 

6-person 21.8 15.0 8.9 

Table 36: Percentage Table for Fire Out begin time

(See Figure 72)

Crew Size 3-person 4-person 5-person 6-person 

3-person -9.1 -11.5 -47.5 

4-person 8.4 -2.2 -35.1 

5-person 10.3 2.1 -32.2 

6-person 32.2 26.0 24.4 

Table 37: Percentage Table for Fire Out duration (See Figure 72)

Crew Size 3-person 4-person 5-person 6-person 

3-person -8.9 -14.5 -34.5 

4-person 8.1 -5.2 -23.5 

5-person 12.7 5.0 -17.4 

6-person 25.6 19.0 14.8 

Table 38: Percentage Table for Fire Out end time (See Figure 72)

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Search and Rescue 10th Floor: Begin time, duration,

and end time

Crew Size 3-person 4-person 5-person 6-person 

3-person -8.7 -16.4 -27.7 

4-person 7.8 -7.1 -17.5 

5-person 14.1 6.7 -9.7 

6-person 21.7 14.9 8.8 

Table 39: Percentage Table for Search and Rescue 10th Floor

begin time (See Figure 73)

Crew Size 3-person 4-person 5-person 6-person 

3-person -28.9 -102.2 -118.2 

4-person 22.4 -56.8 -69.3 

5-person 50.5 36.2 -7.9 

6-person 54.2 40.9 7.3 

Table 40: Percentage Table for Search and Rescue 10th Floor

duration (See Figure 73)

Crew Size 3-person 4-person 5-person 6-person 

3-person -22.5 -67.4 -82.0 

4-person 18.4 -36.7 -48.5 

5-person 40.3 26.8 -8.7 

6-person 45.0 32.7 8.0 

Table 41: Percentage Table for Search and Rescue 10th Floor

end time (See Figure 73)

Victim #1 Found: Begin time, duration, and end time

Crew Size 3-person 4-person 5-person 6-person 

3-person -8.75 -16.4 -27.7 

4-person 7.8 -7.1 -17.5 

5-person 14.1 6.7 -9.7 

6-person 21.7 14.9 8.8 

Table 42: Percentage Table for Victim #1 Found begin time

(See Figure 74)

Crew Size 3-person 4-person 5-person 6-person 

3-person -56.9 -234.1 -316.6 

4-person 36.3 -113.0 -165.5 

5-person 70.1 53.0 -24.7 

6-person 76.0 62.3 19.8 

Table 43: Percentage Table for Victim #1 Found duration

(See Figure 74)

Crew Size 3-person 4-person 5-person 6-person 

3-person -35.9 -102.5 -133.2 

4-person 26.4 -49.0 -71.6 

5-person 50.6 32.9 -15.2 

6-person 57.1 41.7 13.2 

Table 44: Percentage Table for Victim #1 Found end time

(See Figure 74)

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Victim #1 Rescue: Begin time, duration, and end time

Crew Size 3-person 4-person 5-person 6-person 

3-person -35.9 -102.5 -133.2 

4-person 26.4 -49.0 -71.6 

5-person 50.6 32.9 -15.2 

6-person 57.1 41.7 13.2 

Table 45: Percentage Table for Victim # 1 Rescue begin

time (See Figure 75)

Crew Size 3-person 4-person 5-person 6-person 

3-person 0.7 16.1 13.6 

4-person -0.7 15.5 13.0 

5-person -19.2 -18.4 -3.0 

6-person -15.8 -15.0 2.9 

Table 46: Percentage Table for Victim # 1 Rescue duration

(See Figure 75)

Crew Size 3-person 4-person 5-person 6-person 

3-person -33.6 -90.0 -116.0 

4-person 25.1 -42.2 -61.7 

5-person 47.4 29.7 -13.7 

6-person 53.7 38.1 12.0 

Table 47: Percentage Table for Victim # 1 Rescue end time

(See Figure 75)

Victim #1 Descent: Begin time, duration, and end time

Crew Size 3-person 4-person 5-person 6-person 

3-person -30.5 -83.1 -107.7 

4-person 23.4 -40.4 -59.2 

5-person 45.4 28.8 -13.4 

6-person 51.9 37.2 11.8 

Table 48: Percentage Table for Victim #1 Descent begin

time (See Figure 76)

Crew Size 3-person 4-person 5-person 6-person 

3-person 21.1 13.4 13.4 

4-person -26.8 -9.9 -9.9 

5-person -15.4 9.0 0.0 

6-person -15.4 9.0 0.0 

Table 49: Percentage Table for Victim #1 Descent duration

(See Figure 76)

Crew Size 3-person 4-person 5-person 6-person 

3-person -27.4 -75.8 -97.68 

4-person 21.5 -38.0 -55.1 

5-person 43.1 27.5 -12.4 

6-person 49.4 35.5 11.0 

Table 50: Percentage Table for Victim #1 Descent end time

(See Figure 76)

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Advance Line Above the Fire (11th Floor): Begin time,

duration, and end time

Crew Size 3-person 4-person 5-person 6-person 

3-person -1.1 -8.9 -10.3 

4-person 1.09 -7.8 -9.1 

5-person 8.21 7.2 -1.3 

6-person 9.37 8.4 1.3 

Table 51: Percentage Table for Advance Line Above the Fire begin

time (See Figure 77)

Crew Size 3-person 4-person 5-person 6-person 

3-person -42.3 -59.1 -103.5 

4-person 29.7 -11.8 -43.0 

5-person 37.1 10.6 -27.9 

6-person 50.9 30.1 21.8 

Table 52: Percentage Table for Advance Line Above the Fire duration

(See Figure 77)

Crew Size 3-person 4-person 5-person 6-person 

3-person -4.4 -13.0 -16.3 

4-person 4.3 -8.2 -11.3 

5-person 11.5 7.5 -2.9 

6-person 14.0 10.2 2.8 

Table 53: Percentage Table for Advance Line Above the Fire end

time (See Figure 77)

Search and Rescue 11th Floor: Begin time, duration, and

end time

Crew Size 3-person 4-person 5-person 6-person 

3-person -1.2 -8.6 -8.3 

4-person 1.2 -7.3 -7.1 

5-person 7.9 6.8 0.2 

6-person 7.7 6.6 -0.2 

Table 54: Percentage Table for Search and Rescue 11th Floor begin

time (See Figure 78)

Crew Size 3-person 4-person 5-person 6-person 

3-person -49.1 -58.1 -84.8 

4-person 32.9 -6.0 -23.9 

5-person 36.7 5.7 -16.9 

6-person 45.9 19.3 14.4 

Table 55: Percentage Table for Search and Rescue 11th Floor

duration (See Figure 78)

Crew Size 3-person 4-person 5-person 6-person 

3-person -22.9 -31.1 -40.1 

4-person 18.6 -6.7 -14.0 

5-person 23.7 6.3 -6.7 

6-person 28.6 12.3 6.4 

Table 56: Percentage Table for Search and Rescue 11th Floor end

time (See Figure 78)

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Victim #2 Found: Begin time, duration, and end time

Crew Size 3-person 4-person 5-person 6-person 

3-person -2.9 -8.6 -9.0 

4-person 2.8 -5.7 -5.8 

5-person 8.1 5.4 -0.1 

6-person 8.2 5.5 0.1 

Table 57: Percentage Table for Victim #2 Found begin time

(See Figure 79)

Crew Size 3-person 4-person 5-person 6-person 

3-person -103.3 -127.7 -129.5 

4-person 50.8 -12.0 -12.9 

5-person 56.1 10.7 -0.8 

6-person 56.4 11.4 0.8 

Table 58: Percentage Table for Victim #2 Found duration

(See Figure 79)

Crew Size 3-person 4-person 5-person 6-person 

3-person -40.3 -51.6 -52.1 

4-person 28.7 -8.0 -8.4 

5-person 34.0 7.4 -0.3 

6-person 34.3 7.7 0.3 

Table 59: Percentage Table for Victim #2 Found end time

(See Figure 79)

Victim #2 Rescue: Begin time, duration, and end time

Crew Size 3-person 4-person 5-person 6-person 

3-person -40.3 -51.6 -52.1 

4-person 28.7 -8.0 -8.4 

5-person 34.0 7.4 -0.3 

6-person 34.2 7.7 0.3 

Table 60: Percentage Table for Victim #2 Rescue begin time

(See Figure 80)

Crew Size 3-person 4-person 5-person 6-person 

3-person 6.0 9.0 6.7 

4-person -6.3 3.2 0.7 

5-person -9.9 -3.3 -2.6 

6-person -7.0 -0.7 2.6 

Table 61: Percentage Table for Victim #2 Rescue duration

(See Figure 80)

Crew Size 3-person 4-person 5-person 6-person 

3-person -37.4 -47.2 -48.0 

4-person 27.2 -7.2 -7.7 

5-person 32.1 6.7 -0.51 

6-person 32.4 7.1 0.5 

Table 62: Percentage Table for Victim #2 Rescue end time

(See Figure 80)

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Victim #2 Descent: Begin time, duration, and end time

Table 63: Percentage Table for Victim #2 Descent begin time

(See Figure 81)

Crew Size 3-person 4-person 5-person 6-person 

3-person -35.7 -43.6 -46.1 

4-person 26.3 -5.9 -7.7 

5-person 30.4 5.5 -1.7 

6-person 31.6 7.1 1.7 

Table 64: Percentage Table for Victim #2 Descent duration

(See Figure 81)

Crew Size 3-person 4-person 5-person 6-person 

3-person -34.8 -41.6 -46.3 

4-person 25.8 -5.1 -8.5 

5-person 29.4 4.8 -3.3 

6-person 31.6 7.8 3.2 

Table 65: Percentage Table for Victim #2 Descent end time

(See Figure 81)

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Appendix F: Measurement and Model Uncertainty
 

The measurements of length and time taken in these

experiments have unique components of uncertainty that

must be evaluated in order to determine the fidelity of the

data. These components of uncertainty can be grouped into two

categories: Type A and Type B. Type A uncertainties are those

evaluated by statistical methods, such as calculating the standard

deviation of the mean of a set of measurements. Type B

uncertainties are based on scientific judgment using all available

and relevant information. Using relevant information, the upper

and lower limits of the expected value are estimated so that the

probability that the measurement falls within these limits is

essentially 100 %.After all the component uncertainties of a

measurement have been identified and evaluated it is necessary to

use them to compute the combined standard uncertainty using the

law of propagation of uncertainty (the “root sum of squares”).

Although this expresses the uncertainty of a given measurement to

about 60 % confidence, it is useful to define an interval for which

the measurement will fall within a high level of statistical

confidence. This is known as the expanded uncertainty. The current

international practice is to multiply the combined standard

uncertainty by a factor of two (k=2), giving a confidence of 95 %.

To construct a geometrically accurate computer model of the

high­rise floor to use in the fire simulations, the structure

dimensions needed to be accurately measured. Long

measurements such as hallway and corridor lengths were taken

using a HILTI PD20 laser range meter. The estimated accuracy of

the laser is 0.19 in (3 mm) over an operating range of greater than

330 ft (100 m). The large­scale measurements were on the order

of 100 ft (30 m) to 140 ft (40 m). This leads to an uncertainty of ±

0.01 %. Shorter length measurements such as door openings,

cubicle sizes, and button locations were taken using a measuring

tape with a resolution of 0.02 in (0.5 mm). However,

measurement error due to uneven and non­level surfaces resulted

in an estimated uncertainty of ± 0.5 % for length measurements

taken on the scale of room dimensions. Taking a conservative

approach, the small­scale measurement uncertainty was

considered for all measurements. Therefore, the estimated total

expanded uncertainty for length measurements was ± 1.0 %.

All timing staff were equipped with the same model of digital

stopwatch with a resolution of 0.01 s and an uncertainty of ± 3 s

per 24 hr; the uncertainty of the timing mechanism in the

stopwatches was small enough over the duration of an experiment

that it can be neglected. There are three components of

uncertainty when using people to time firefighting tasks. First,

timers may have a bias depending on whether they record the

time in anticipation of, or reaction to an event. A second

component exists because multiple timers were used to record all

tasks. The third component is the mode of the stimulus to which

the staff is reacting: audible (firefighters announcing task updates

over the radio) or visual (timing staff sees a task start or stop).

Milestone events in these experiments were recorded both audibly

and visually.A test series described in the NIST Recommended

Practice Guide for Stopwatch and Timer Calibrations (Gust et al.,

2009) found the reaction times for the two modes of stimulus to be

approximately the same,so this component can be neglected.

Because of the lack of knowledge regarding the mean bias of the

timers, a rectangular distribution was assumed and the worst case

reaction time bias of 120 ms was used, giving a standard deviation of

69 ms. The standard deviation of the reaction time was assumed to

be the worst case of 230 ms. The estimated total expanded

uncertainty of task times measured in these experiments was 240 ms.

An additional component of uncertainty exists for the firefighters

pressing the target buttons on the fire floor. The target buttons on

the fire floor were located along one of the three interior walls of the

cubicles. The location of the button within the cubicle was random

to force firefighters to search the entire cubicle and not become

conditioned to search just one wall. There was no experimental

procedure set for searching the cubicles, just a directive to search the

entire cubicle.While the individual cubicles were small, the search

could have been conducted in a variety of manners depending on

the individual firefighter. From experimental observations a

reasonable estimate for the time it takes to search a cubicle and press

the button, when applicable, is 6 s with a standard deviation of ± 2 s.

This results in an expanded uncertainty of ± 4 s.

A summary of experimental measurement uncertainty is given

in Table 66.

Measurement Component Standard

Uncertainty 

Combined Standard 

Uncertainty 

Total Expanded

Uncertainty 

Length Measurements 

Cubicle Dimensions ± 0.5 % 

Building Dimensions ± 0.5 % 

± 1 % ± 2 % 

Timer Data 

Timer Bias ± 0.069 s 

Reaction Time ± 0.230 s 

± 0.299 s ± 0.598 s 

Button Time Data 

Finding/Pressing Buttons Elevator ± 2 s ± 4 s 

Table 66: Summary of Measurement Uncertainty

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In addition to experimental uncertainty, there exists uncertainty

in the computational models. Models are used when the

equations describing the governing physics of a problem cannot

be solved directly. To test the ability of a model to correctly

capture the chemistry and physics, the computational software

must be validated by testing against experimental results. The FDS

model used for the simulations in this report undergoes extensive

and on­going validation (McGrattan et al. 2012c, USNRC 2007).

For questions regarding air tenability, the parameter of interest is

the fractional effective dose (FED)31. According to ISO 13571, the

exact distribution of human response to toxic gas inhalation is

not known. As a result, there is considerable uncertainty relating

the computed FED value from the computation model to the

percentage of the population likely to be incapacitated. According

to the ISO standard for the gases considered in this study, the

uncertainty can be as much as ± 20 % to 35 % (ISO 13571).

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Appendix G: Development of a Design Fire
 

The first step in calculating a design fire is to determine what

fuel or fuels could be used to represent a cubicle. Cubicles are

generally composed of a wide range of combustibles, from

natural materials (such as wood furniture and paper) to synthetics

(such as foam padding and plastic computers). Instead of modeling

each individual component, the composition of the cubicle was

lumped into a natural or wood component and a synthetic or plastic

(polyurethane) component, based on mass composition. This

resulted in a source fire whose fuel was composed of 70 % wood and

30 % polyurethane by mass (Ohlemiller et al. 2005). Determination

of the representative fuels for the fire is important because each fuel

consumes oxygen at a different rate,releases different amounts of

energy, produces different amounts of carbon monoxide and soot,

and has different extinction criteria. Table 67 shows properties of

interest for two fuels.

From Table 67, polyurethane has a larger heat of combustion than

wood, which means that it releases more energy per kilogram of fuel

consumed. However, wood makes up 70 % of the fuel load in the

cubicle, so wood is responsible for a larger portion of the total energy

release. Polyurethane has a carbon monoxide yield that is

approximately an order of magnitude larger than that of wood. The

difference in carbon monoxide yields illustrates the need for a

multi­fuel source fire, as carbon monoxide is one of the three Figure 104: Heat release rate versus time of a typical single contributing species to the FED analysis performed for this report. workstation fire from the Cook County Administration building To determine the remaining parameters for constructing the design (Madrzykowski et al. 2004)

fire curve, experiments performed as part of the NIST study of the

Cook County Administration building

fire were examined (Madrzykowski et al.

2004). Part of the incident reconstruction

work conducted by NIST scientists

included performing fire tests of a single

workstation under a full­scale

calorimeter.A calorimeter is an

experimental apparatus used to

determine the heat release rate of an

Fuel Chemical 

Formula 

Heat of Combustion 

(kJ/kg) CO Yield Soot Yield 

Wood C25H42O6N2 16400 0.004 0.015 

Polyurethane CH1.7N0.74O0.002 26200 0.01 0.131 

Table 67: Fuel properties and product yields for fuel components of design fire (Tewarson 2008).

object or set of objects. Heat

release rate (HRR) is the

amount of energy released per

unit of time from the fire. Figure

104 shows the HRR as a

function of time from ignition

until burnout for a typical single

workstation in the Cook County

Administration building. To

better understand the

magnitude of the values in

Figure 104, Table 68 shows

common objects and their peak

HRR values found from

calorimeter experiments.

0 6 12 18 24 30 

0 

0.5 

1 

1.5 

2 

2.5 

3 

3.5 

Time (min) 

Heat Release Rate (MW) 

Single Workstation 

Peak Heat Release Rate Object Source 

5 W Burning cigarette Babrauskas et al. 1985 

80 W Burning match or candle Babrauskas et al. 1985, 

Hamins et al. 2005 

30 kW to 300 kW 

Small Plastic Waste Container 

to Large (30 gal) Waste

Container 

Stroup et al. 2003, 

Madrzykowski et al. 2009 

80 kW to 2.5 MW Burning Upholstered Chair Madrzykowski et al. 2009, 

Stroup et al. 2001, DCA 1991 

2.5 MW to 5 MW Burning Upholstered Sofa Madrzykowski et al. 2009 

1.5 MW to 5 MW Burning Christmas Tree Stroup et al. 1999, 

Madryzkowski 2008 

30 MW Rail Car Babrauskas, 2008 

Table 68: Peak heat release rate values from common objects

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The next step in building the design fire curves was to determine

the criteria for ignition of adjacent cubicles. In addition to

conducting fire tests on single cubicles, NIST scientists also

conducted calorimeter tests for multiple cubicles (Madrzykowski

et al. 2004). The experiments noted the time at which an adjacent

cubicle ignited. From this time, the total amount of energy that

needed to be released for ignition was found, approximately 600

MJ (cf. Figure 105).

This critical total energy value was used as the criteria for fire

spread to adjacent cubicles in the computer model. The vertical

line in Figure 105 indicates when ignition occurred. In the model,

fire spread meant invoking additional design fire curves. If more

than one fire is burning at a given time, then the total HRR is the

sum of the HRR values from each active cubicle fire. Since fire

spread is based on total energy released, the faster growth rate

design fires spread faster.

0 2 4 6 8 

0 

5 

10 

15 

20 

25 

Time (min) 

Heat Release Rate (MW) 

Multi−Workstation 

Ignition of Adjacent Cubicle 

Figure 105: Heat release rate versus time curve showing ignition of

an adjacent cubicle from the Cook County Administration building

experiments (Madrzykowski et al. 2004)

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http://dx.doi.org/10.6028/NIST.TN.1797